diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b25c85..6bc47e1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,11 +2,19 @@
 
 All notable changes to this project will be documented in this file. Dates are displayed in UTC.
 
-#### [v0.5.2](https://git.odit.services/lfk/document-server/compare/v0.5.1...v0.5.2)
+#### [v0.5.3](https://git.odit.services/lfk/document-server/compare/v0.5.1...v0.5.3)
 
 - Merge branch 'bugfix/44-runner-certificates-result-in-a-status-500' into dev [`#44`](https://git.odit.services/lfk/document-server/issues/44)
+- Fixed Locale comma format [`2a33226`](https://git.odit.services/lfk/document-server/commit/2a3322612d473bd9002cf8d6f9807f9dc7d687da)
 - wrap distanceDonations.reduce in array length check [`bac004d`](https://git.odit.services/lfk/document-server/commit/bac004d74eb954d1753d4efcdb927822b89fa757)
 - 🧾New changelog file version [CI SKIP] [skip ci] [`ff0421d`](https://git.odit.services/lfk/document-server/commit/ff0421da2f16a8f79f9987dabea7bdcb4ef88c05)
+- 🧾New changelog file version [CI SKIP] [skip ci] [`f846572`](https://git.odit.services/lfk/document-server/commit/f8465721cddfb55d51eb30d29d74ef63d825b5ac)
+- Fix for runner donation array [`72303b1`](https://git.odit.services/lfk/document-server/commit/72303b11052276ad15373887f9e04183841f56f4)
+- 🧾New changelog file version [CI SKIP] [skip ci] [`451b7fb`](https://git.odit.services/lfk/document-server/commit/451b7fbe0543991e8a203e38daa350a954ae0e11)
+- 🧾New changelog file version [CI SKIP] [skip ci] [`573b921`](https://git.odit.services/lfk/document-server/commit/573b9211972a55df0a38742cb6eb789d6fd3717b)
+- 🚀Bumped version to v0.5.3 [`01e1323`](https://git.odit.services/lfk/document-server/commit/01e1323555fe67f6f0ce3c18163e475035bd1cdd)
+- 🧾New changelog file version [CI SKIP] [skip ci] [`4b4d66a`](https://git.odit.services/lfk/document-server/commit/4b4d66ae784150f7e1cc491a3fc5d84c93273aee)
+- Merge pull request 'v0.5.2: hotfix TypeError in Runner Certificate generation' (#45) from dev into main [`c935950`](https://git.odit.services/lfk/document-server/commit/c935950eb052bce71185fc74c750ec77f081e7df)
 - 🚀Bumped version to v0.5.2 [`274c13e`](https://git.odit.services/lfk/document-server/commit/274c13e358f16207fe8bb5cdc1b9ede0582ecb46)
 - 🧾New changelog file version [CI SKIP] [skip ci] [`b7b7f6a`](https://git.odit.services/lfk/document-server/commit/b7b7f6a0ae304d24f90a3de3931f53cf08770060)
 
diff --git a/package.json b/package.json
index 025141c..d296d95 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@odit/lfk-document-server",
-  "version": "0.5.2",
+  "version": "0.5.3",
   "description": "The document generation server for the LfK! runner system. This generates certificates, sponsoring aggreements and more",
   "main": "src/app.ts",
   "scripts": {
diff --git a/src/PdfCreator.ts b/src/PdfCreator.ts
index e3446ce..f6ff3ff 100644
--- a/src/PdfCreator.ts
+++ b/src/PdfCreator.ts
@@ -1,308 +1,308 @@
-import axios from 'axios';
-import cheerio from "cheerio";
-import fs from "fs";
-import Handlebars from 'handlebars';
-import i18next from "i18next";
-import Backend from 'i18next-fs-backend';
-import mime from "mime-types";
-import path from 'path';
-import { PDFDocument } from 'pdf-lib';
-import puppeteer from "puppeteer";
-import { awaitAsyncHandlebarHelpers, helpers } from './asyncHelpers';
-import { config } from './config';
-import { CertificateRunner } from './models/CertificateRunner';
-import { Runner } from './models/Runner';
-import { RunnerCard } from './models/RunnerCard';
-import { RunnerGroup } from './models/RunnerGroup';
-
-/**
- * This class is responsible for all things pdf creation.
- * This uses the html templates from src/templates.
- */
-export class PdfCreator {
-    private templateDir = path.join(__dirname, '/templates');
-    private browser;
-    private static interpolations = { eventname: config.eventname, sponsoring_receipt_minimum_amount: config.sponsoring_receipt_minimum_amount, currency_symbol: config.currency_symbol }
-    private static contractsPerRunner = config.contracts_per_runner;
-
-    /**
-     * Main constructor.
-     * Initializes i18n(ext), Handlebars and puppeteer.
-     */
-    constructor() {
-        this.init();
-    }
-
-    /**
-     * Main constructor.
-     * Initializes i18n(ext), Handlebars and puppeteer.
-     */
-    public async init() {
-        const minimal_args = [
-            '--autoplay-policy=user-gesture-required',
-            '--disable-background-networking',
-            '--disable-background-timer-throttling',
-            '--disable-backgrounding-occluded-windows',
-            '--disable-breakpad',
-            '--disable-client-side-phishing-detection',
-            '--disable-component-update',
-            '--disable-default-apps',
-            '--disable-dev-shm-usage',
-            '--disable-domain-reliability',
-            '--disable-extensions',
-            '--disable-features=AudioServiceOutOfProcess',
-            '--disable-hang-monitor',
-            '--disable-ipc-flooding-protection',
-            '--disable-notifications',
-            '--disable-offer-store-unmasked-wallet-cards',
-            '--disable-popup-blocking',
-            '--disable-print-preview',
-            '--disable-prompt-on-repost',
-            '--disable-renderer-backgrounding',
-            '--disable-speech-api',
-            '--disable-sync',
-            '--hide-scrollbars',
-            '--ignore-gpu-blacklist',
-            '--metrics-recording-only',
-            '--mute-audio',
-            '--no-default-browser-check',
-            '--no-first-run',
-            '--no-pings',
-            '--no-zygote',
-            '--password-store=basic',
-            '--use-gl=swiftshader',
-            '--no-sandbox'
-        ];
-        await i18next
-            .use(Backend)
-            .init({
-                fallbackLng: 'en',
-                lng: 'en',
-                backend: {
-                    loadPath: path.join(__dirname, '/locales/{{lng}}.json')
-                }
-            });
-
-        await Handlebars.registerHelper(helpers);
-        await Handlebars.registerHelper('__',
-            function (str) {
-                return i18next.t(str, PdfCreator.interpolations).toString();
-            }
-        );
-        await Handlebars.registerHelper('--sponsor',
-            function (str) {
-                const index = (parseInt(str) % config.sponor_logos.length);
-                if (isNaN(index)) {
-                    return "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+P+/HgAFhAJ/wlseKgAAAABJRU5ErkJggg=="
-                }
-                return config.sponor_logos[index];
-            }
-        );
-        await Handlebars.registerHelper('--format_kilometers',
-            function (str) {
-                let meters = parseInt(str);
-                return ((meters / 1000).toFixed(3).toString())
-            }
-        );
-        await Handlebars.registerHelper('--format_currency',
-            function (str) {
-                let meters = parseInt(str);
-                return ((meters / 100).toFixed(2).toString())
-            }
-        );
-        this.browser = await puppeteer.launch({ headless: true, args: minimal_args });
-    }
-
-    /**
-     * Generate sponsoring contract pdfs.
-     * @param runner The runner you want to generate the contracts for.
-     * @param locale The locale used for the contracts (default:en)
-     */
-    public async generateSponsoringContract(runners: Runner[], locale: string = "en", codeformat: string = config.codeformat): Promise<Buffer> {
-        if (runners.length == 1 && Object.keys(runners[0]).length == 0) {
-            runners[0] = this.generateEmptyRunner();
-        }
-        if (runners.length > 50) {
-            let pdf_promises = new Array<Promise<Buffer>>();
-            let i, j;
-            for (i = 0, j = runners.length; i < j; i += 50) {
-                let chunk = runners.slice(i, i + 50);
-                pdf_promises.push(this.generateSponsoringContract(chunk, locale));
-            }
-            const pdfs = await Promise.all(pdf_promises);
-            return await this.mergePdfs(pdfs);
-        }
-        for (var i = 1; i < PdfCreator.contractsPerRunner; i++) {
-            runners = runners.reduce(function (res, current, index, array) {
-                return res.concat([current, current]);
-            }, []);
-        }
-        await i18next.changeLanguage(locale);
-        const template_source = fs.readFileSync(`${this.templateDir}/sponsoring_contract.html`, 'utf8');
-        const template = Handlebars.compile(template_source);
-        let result = template({ runners, codeformat, disclaimer: config.disclaimer_text });
-        result = await awaitAsyncHandlebarHelpers(result);
-        const pdf = await this.renderPdf(result, { format: "A5", landscape: true });
-        return pdf
-    }
-
-    /**
-     * Generate runner card pdfs.
-     * @param cards The runner cars you want to generate the cards for.
-     * @param locale The locale used for the cards (default:en)
-     */
-    public async generateRunnerCards(cards: RunnerCard[], locale: string = "en", codeformat: string = config.codeformat_cards): Promise<Buffer> {
-        if (cards.length > 10) {
-            let pdf_promises = new Array<Promise<Buffer>>();
-            let i, j;
-            for (i = 0, j = cards.length; i < j; i += 10) {
-                let chunk = cards.slice(i, i + 10);
-                pdf_promises.push(this.generateRunnerCards(chunk, locale, codeformat));
-            }
-            const pdfs = await Promise.all(pdf_promises);
-            return await this.mergePdfs(pdfs);
-        }
-        const cards_swapped = this.swapArrayPairs(cards);
-        await i18next.changeLanguage(locale);
-        const template_source = fs.readFileSync(`${this.templateDir}/runner_card.html`, 'utf8');
-        const template = Handlebars.compile(template_source);
-        let result = template({ cards, cards_swapped, eventname: config.eventname, codeformat: codeformat, card_subtitle: config.card_subtitle })
-        result = await awaitAsyncHandlebarHelpers(result);
-        const pdf = await this.renderPdf(result, { format: "A4", landscape: false });
-        return pdf
-    }
-
-    /**
-     * Generate sponsoring contract pdfs.
-     * @param runner The runner you want to generate the contracts for.
-     * @param locale The locale used for the contracts (default:en)
-     */
-    public async generateRunnerCertficates(runners: CertificateRunner[], locale: string = "en"): Promise<Buffer> {
-        if (runners.length > 50) {
-            let pdf_promises = new Array<Buffer>();
-            let i, j;
-            for (i = 0, j = runners.length; i < j; i += 50) {
-                let chunk = runners.slice(i, i + 50);
-                pdf_promises.push(await this.generateRunnerCertficates(chunk, locale));
-            }
-            return await this.mergePdfs(pdf_promises);
-        }
-        await i18next.changeLanguage(locale);
-        const template_source = fs.readFileSync(`${this.templateDir}/runner_certificate.html`, 'utf8');
-        const template = Handlebars.compile(template_source);
-        let result = template({ runners, eventname: config.eventname, currency_symbol: config.currency_symbol, donations_footer_text: config.donations_footer_text });
-        result = await awaitAsyncHandlebarHelpers(result);
-        const pdf = await this.renderPdf(result, { format: "A4", landscape: false, printBackground: true });
-        return pdf;
-    }
-
-    /**
-     * Converts all images in html to base64.
-     * Works with image files in the template directory or images from urls.
-     * @param html The html string whoms images shall get replaced.
-     */
-    public async imgToBase64(html): Promise<string> {
-        const $ = cheerio.load(html)
-
-        $('img').each(async (index, element) => {
-            let imgsrc = $(element).attr("src");
-            if (imgsrc.startsWith("data:image")) {
-                return;
-            }
-            const img_type = mime.lookup(imgsrc);
-
-            if (!(img_type.includes("image"))) {
-                throw new Error("File is not image mime type");
-            }
-
-            let image;
-            if (imgsrc.startsWith("http")) {
-                image = (await axios.get(imgsrc)).data;
-                image = Buffer.from(image).toString('base64');
-            }
-            else {
-                if (imgsrc.startsWith("./")) {
-                    imgsrc = imgsrc.replace("./", "");
-                }
-                image = fs.readFileSync(`${this.templateDir}/${imgsrc}`, { encoding: "base64" });
-            }
-
-            image = `data:${img_type};base64,${image}`
-            $(element).attr("src", image)
-        });
-
-        return $.html();
-    }
-
-    /**
-     * This method manages the creation of pdfs via puppeteer.
-     * @param html The HTML that should get rendered.
-     * @param options Puppeteer PDF option (eg: {format: "A4"})
-     */
-    public async renderPdf(html: string, options): Promise<any> {
-        html = await this.imgToBase64(html);
-        let page = await this.browser.newPage();
-        await page.setContent(html);
-        const pdf = await page.pdf(options);
-        await page.close();
-        return pdf;
-    }
-
-    /**
-     * Merges multiple pdfs into one.
-     * @param pdfs The pdfs you want to merge as an buffer array.
-     * @returns The merged pdf as a buffer.
-     */
-    private async mergePdfs(pdfs: Buffer[]): Promise<Buffer> {
-        const mergedPdf = await PDFDocument.create();
-
-        for (const pdfBuffer of pdfs) {
-            const pdf = await PDFDocument.load(pdfBuffer);
-            const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
-            copiedPages.forEach((page) => {
-                mergedPdf.addPage(page);
-            });
-        }
-
-        return <Buffer>(await mergedPdf.save());
-    }
-
-    /**
-     * Generates a new dummy runner with halfspaces for all strings.
-     * Can be used to generate empty sponsoring contracts.
-     * @returns A new runner object that apears to be empty.
-     */
-    private generateEmptyRunner(): Runner {
-        let group = new RunnerGroup();
-        group.id = 0;
-        group.name = " ";
-        let runner = new Runner();
-        runner.id = 0;
-        runner.firstname = " ";
-        runner.lastname = " ";
-        runner.group = group;
-        return runner;
-    }
-
-    /**
-     * Swaps pairs (0/1, 2/3, ...) of elements in an array recursively.
-     * If the last element has no partner it inserts an empty element at the end and swaps the two
-     * This is needed to generate pdfs with front- and backside that get printet on one paper.
-     * @param array The array which's pairs shall get switched.
-     * @returns Array with swapped pairs,
-     */
-    private swapArrayPairs(array): Array<any> {
-        if (array.length == 1) {
-            return [null, array[0]];
-        }
-        if (array.length == 0) {
-            return null;
-        }
-
-        const rest = this.swapArrayPairs(array.slice(2))
-        if (!rest) {
-            return [array[1], array[0]]
-        }
-        return [array[1], array[0]].concat(rest);
-    }
+import axios from 'axios';
+import cheerio from "cheerio";
+import fs from "fs";
+import Handlebars from 'handlebars';
+import i18next from "i18next";
+import Backend from 'i18next-fs-backend';
+import mime from "mime-types";
+import path from 'path';
+import { PDFDocument } from 'pdf-lib';
+import puppeteer from "puppeteer";
+import { awaitAsyncHandlebarHelpers, helpers } from './asyncHelpers';
+import { config } from './config';
+import { CertificateRunner } from './models/CertificateRunner';
+import { Runner } from './models/Runner';
+import { RunnerCard } from './models/RunnerCard';
+import { RunnerGroup } from './models/RunnerGroup';
+
+/**
+ * This class is responsible for all things pdf creation.
+ * This uses the html templates from src/templates.
+ */
+export class PdfCreator {
+    private templateDir = path.join(__dirname, '/templates');
+    private browser;
+    private static interpolations = { eventname: config.eventname, sponsoring_receipt_minimum_amount: config.sponsoring_receipt_minimum_amount, currency_symbol: config.currency_symbol }
+    private static contractsPerRunner = config.contracts_per_runner;
+
+    /**
+     * Main constructor.
+     * Initializes i18n(ext), Handlebars and puppeteer.
+     */
+    constructor() {
+        this.init();
+    }
+
+    /**
+     * Main constructor.
+     * Initializes i18n(ext), Handlebars and puppeteer.
+     */
+    public async init() {
+        const minimal_args = [
+            '--autoplay-policy=user-gesture-required',
+            '--disable-background-networking',
+            '--disable-background-timer-throttling',
+            '--disable-backgrounding-occluded-windows',
+            '--disable-breakpad',
+            '--disable-client-side-phishing-detection',
+            '--disable-component-update',
+            '--disable-default-apps',
+            '--disable-dev-shm-usage',
+            '--disable-domain-reliability',
+            '--disable-extensions',
+            '--disable-features=AudioServiceOutOfProcess',
+            '--disable-hang-monitor',
+            '--disable-ipc-flooding-protection',
+            '--disable-notifications',
+            '--disable-offer-store-unmasked-wallet-cards',
+            '--disable-popup-blocking',
+            '--disable-print-preview',
+            '--disable-prompt-on-repost',
+            '--disable-renderer-backgrounding',
+            '--disable-speech-api',
+            '--disable-sync',
+            '--hide-scrollbars',
+            '--ignore-gpu-blacklist',
+            '--metrics-recording-only',
+            '--mute-audio',
+            '--no-default-browser-check',
+            '--no-first-run',
+            '--no-pings',
+            '--no-zygote',
+            '--password-store=basic',
+            '--use-gl=swiftshader',
+            '--no-sandbox'
+        ];
+        await i18next
+            .use(Backend)
+            .init({
+                fallbackLng: 'en',
+                lng: 'en',
+                backend: {
+                    loadPath: path.join(__dirname, '/locales/{{lng}}.json')
+                }
+            });
+
+        await Handlebars.registerHelper(helpers);
+        await Handlebars.registerHelper('__',
+            function (str) {
+                return i18next.t(str, PdfCreator.interpolations).toString();
+            }
+        );
+        await Handlebars.registerHelper('--sponsor',
+            function (str) {
+                const index = (parseInt(str) % config.sponor_logos.length);
+                if (isNaN(index)) {
+                    return "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+P+/HgAFhAJ/wlseKgAAAABJRU5ErkJggg=="
+                }
+                return config.sponor_logos[index];
+            }
+        );
+        await Handlebars.registerHelper('--format_kilometers',
+            function (str) {
+                let meters = parseInt(str);
+                return ((meters / 1000).toLocaleString("de-DE", { minimumFractionDigits: 1, maximumFractionDigits: 3 }))
+            }
+        );
+        await Handlebars.registerHelper('--format_currency',
+            function (str) {
+                let meters = parseInt(str);
+                return ((meters / 100).toLocaleString("de-DE", { minimumFractionDigits: 2, maximumFractionDigits: 2 }))
+            }
+        );
+        this.browser = await puppeteer.launch({ headless: true, args: minimal_args });
+    }
+
+    /**
+     * Generate sponsoring contract pdfs.
+     * @param runner The runner you want to generate the contracts for.
+     * @param locale The locale used for the contracts (default:en)
+     */
+    public async generateSponsoringContract(runners: Runner[], locale: string = "en", codeformat: string = config.codeformat): Promise<Buffer> {
+        if (runners.length == 1 && Object.keys(runners[0]).length == 0) {
+            runners[0] = this.generateEmptyRunner();
+        }
+        if (runners.length > 50) {
+            let pdf_promises = new Array<Promise<Buffer>>();
+            let i, j;
+            for (i = 0, j = runners.length; i < j; i += 50) {
+                let chunk = runners.slice(i, i + 50);
+                pdf_promises.push(this.generateSponsoringContract(chunk, locale));
+            }
+            const pdfs = await Promise.all(pdf_promises);
+            return await this.mergePdfs(pdfs);
+        }
+        for (var i = 1; i < PdfCreator.contractsPerRunner; i++) {
+            runners = runners.reduce(function (res, current, index, array) {
+                return res.concat([current, current]);
+            }, []);
+        }
+        await i18next.changeLanguage(locale);
+        const template_source = fs.readFileSync(`${this.templateDir}/sponsoring_contract.html`, 'utf8');
+        const template = Handlebars.compile(template_source);
+        let result = template({ runners, codeformat, disclaimer: config.disclaimer_text });
+        result = await awaitAsyncHandlebarHelpers(result);
+        const pdf = await this.renderPdf(result, { format: "A5", landscape: true });
+        return pdf
+    }
+
+    /**
+     * Generate runner card pdfs.
+     * @param cards The runner cars you want to generate the cards for.
+     * @param locale The locale used for the cards (default:en)
+     */
+    public async generateRunnerCards(cards: RunnerCard[], locale: string = "en", codeformat: string = config.codeformat_cards): Promise<Buffer> {
+        if (cards.length > 10) {
+            let pdf_promises = new Array<Promise<Buffer>>();
+            let i, j;
+            for (i = 0, j = cards.length; i < j; i += 10) {
+                let chunk = cards.slice(i, i + 10);
+                pdf_promises.push(this.generateRunnerCards(chunk, locale, codeformat));
+            }
+            const pdfs = await Promise.all(pdf_promises);
+            return await this.mergePdfs(pdfs);
+        }
+        const cards_swapped = this.swapArrayPairs(cards);
+        await i18next.changeLanguage(locale);
+        const template_source = fs.readFileSync(`${this.templateDir}/runner_card.html`, 'utf8');
+        const template = Handlebars.compile(template_source);
+        let result = template({ cards, cards_swapped, eventname: config.eventname, codeformat: codeformat, card_subtitle: config.card_subtitle })
+        result = await awaitAsyncHandlebarHelpers(result);
+        const pdf = await this.renderPdf(result, { format: "A4", landscape: false });
+        return pdf
+    }
+
+    /**
+     * Generate sponsoring contract pdfs.
+     * @param runner The runner you want to generate the contracts for.
+     * @param locale The locale used for the contracts (default:en)
+     */
+    public async generateRunnerCertficates(runners: CertificateRunner[], locale: string = "en"): Promise<Buffer> {
+        if (runners.length > 50) {
+            let pdf_promises = new Array<Buffer>();
+            let i, j;
+            for (i = 0, j = runners.length; i < j; i += 50) {
+                let chunk = runners.slice(i, i + 50);
+                pdf_promises.push(await this.generateRunnerCertficates(chunk, locale));
+            }
+            return await this.mergePdfs(pdf_promises);
+        }
+        await i18next.changeLanguage(locale);
+        const template_source = fs.readFileSync(`${this.templateDir}/runner_certificate.html`, 'utf8');
+        const template = Handlebars.compile(template_source);
+        let result = template({ runners, eventname: config.eventname, currency_symbol: config.currency_symbol, donations_footer_text: config.donations_footer_text });
+        result = await awaitAsyncHandlebarHelpers(result);
+        const pdf = await this.renderPdf(result, { format: "A4", landscape: false, printBackground: true });
+        return pdf;
+    }
+
+    /**
+     * Converts all images in html to base64.
+     * Works with image files in the template directory or images from urls.
+     * @param html The html string whoms images shall get replaced.
+     */
+    public async imgToBase64(html): Promise<string> {
+        const $ = cheerio.load(html)
+
+        $('img').each(async (index, element) => {
+            let imgsrc = $(element).attr("src");
+            if (imgsrc.startsWith("data:image")) {
+                return;
+            }
+            const img_type = mime.lookup(imgsrc);
+
+            if (!(img_type.includes("image"))) {
+                throw new Error("File is not image mime type");
+            }
+
+            let image;
+            if (imgsrc.startsWith("http")) {
+                image = (await axios.get(imgsrc)).data;
+                image = Buffer.from(image).toString('base64');
+            }
+            else {
+                if (imgsrc.startsWith("./")) {
+                    imgsrc = imgsrc.replace("./", "");
+                }
+                image = fs.readFileSync(`${this.templateDir}/${imgsrc}`, { encoding: "base64" });
+            }
+
+            image = `data:${img_type};base64,${image}`
+            $(element).attr("src", image)
+        });
+
+        return $.html();
+    }
+
+    /**
+     * This method manages the creation of pdfs via puppeteer.
+     * @param html The HTML that should get rendered.
+     * @param options Puppeteer PDF option (eg: {format: "A4"})
+     */
+    public async renderPdf(html: string, options): Promise<any> {
+        html = await this.imgToBase64(html);
+        let page = await this.browser.newPage();
+        await page.setContent(html);
+        const pdf = await page.pdf(options);
+        await page.close();
+        return pdf;
+    }
+
+    /**
+     * Merges multiple pdfs into one.
+     * @param pdfs The pdfs you want to merge as an buffer array.
+     * @returns The merged pdf as a buffer.
+     */
+    private async mergePdfs(pdfs: Buffer[]): Promise<Buffer> {
+        const mergedPdf = await PDFDocument.create();
+
+        for (const pdfBuffer of pdfs) {
+            const pdf = await PDFDocument.load(pdfBuffer);
+            const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
+            copiedPages.forEach((page) => {
+                mergedPdf.addPage(page);
+            });
+        }
+
+        return <Buffer>(await mergedPdf.save());
+    }
+
+    /**
+     * Generates a new dummy runner with halfspaces for all strings.
+     * Can be used to generate empty sponsoring contracts.
+     * @returns A new runner object that apears to be empty.
+     */
+    private generateEmptyRunner(): Runner {
+        let group = new RunnerGroup();
+        group.id = 0;
+        group.name = " ";
+        let runner = new Runner();
+        runner.id = 0;
+        runner.firstname = " ";
+        runner.lastname = " ";
+        runner.group = group;
+        return runner;
+    }
+
+    /**
+     * Swaps pairs (0/1, 2/3, ...) of elements in an array recursively.
+     * If the last element has no partner it inserts an empty element at the end and swaps the two
+     * This is needed to generate pdfs with front- and backside that get printet on one paper.
+     * @param array The array which's pairs shall get switched.
+     * @returns Array with swapped pairs,
+     */
+    private swapArrayPairs(array): Array<any> {
+        if (array.length == 1) {
+            return [null, array[0]];
+        }
+        if (array.length == 0) {
+            return null;
+        }
+
+        const rest = this.swapArrayPairs(array.slice(2))
+        if (!rest) {
+            return [array[1], array[0]]
+        }
+        return [array[1], array[0]].concat(rest);
+    }
 }
\ No newline at end of file
diff --git a/src/controllers/PdfController.ts b/src/controllers/PdfController.ts
index f6d8a52..ba4ee72 100644
--- a/src/controllers/PdfController.ts
+++ b/src/controllers/PdfController.ts
@@ -98,8 +98,10 @@ export class PdfController {
                 runner.group.fullName = `${runner.group.parentGroup.name}/${runner.group.name}`;
             }
             runner.donationPerDistanceTotal = 0;
+            if (!Array.isArray(runner.distanceDonations)){
+                runner.distanceDonations = [].concat(runner.distanceDonations)
+            }
             if (runner.distanceDonations.length > 0) {
-                console.log(typeof runner.distanceDonations);
                 runner.donationPerDistanceTotal += runner.distanceDonations.reduce(function (sum, current) {
                     return sum + current.amountPerDistance;
                 }, 0);