diff --git a/README.asciidoc b/README.asciidoc
index 4ba518d..8e4fbba 100644
--- a/README.asciidoc
+++ b/README.asciidoc
@@ -2,4 +2,6 @@
 :imagesdir: ./media
 :docdir: content
 
-include::main.asciidoc[]
\ No newline at end of file
+NOTE: To build this document you can use the following command: `asciidoctor -r asciidoctor-bibtex main.asciidoc`
+
+include::main.asciidoc[]
diff --git a/bibliography/CodeContender.bib b/bibliography/CodeContender.bib
new file mode 100644
index 0000000..6046ae1
--- /dev/null
+++ b/bibliography/CodeContender.bib
@@ -0,0 +1,7 @@
+
+@misc{noauthor_codegrade_nodate,
+	title = {The {CodeGrade} {Documentation} — {CodeGrade} {QuietStorm}.1 documentation},
+	url = {https://docs.codegra.de/},
+	urldate = {2024-08-25},
+	file = {The CodeGrade Documentation — CodeGrade QuietStorm.1 documentation:/Users/chris/Zotero/storage/K79YSBN2/docs.codegra.de.html:text/html},
+}
diff --git a/content/existing_solutions.asciidoc b/content/existing_solutions.asciidoc
index b735a04..8624b39 100644
--- a/content/existing_solutions.asciidoc
+++ b/content/existing_solutions.asciidoc
@@ -3,12 +3,19 @@ link:https://docs.codegra.de[CodeGra.de]
 
 Commercial solution for grading code submissions in an external tool, integratable via the open LTI interface.
 
+cite:[noauthor_codegrade_nodate]
+
 ==== Features ====
 
 * Automatic grading through unit tests, I/O, error code, linter
 * Inline comments like code review
 * Plagiarism detection to check similarity between submissions
 
+=== CS50 with Check50 ===
+link:https://cs50.readthedocs.io/[CS50]
+The Harvard MOOC which is build upon the edX platform doesn't use a built-in code grading system. Instead, there is a separate tooling called CS50 with multiple checking tools for i.e. linting (style50), plagiarism detection (compare50), 
+
+
 === CodeOcean ===
 
 link:https://codeocean.openhpi.de/[CodeOcean] ist eine webbasierte Plattform für praktische Programmierübungen, die hauptsächlich in MOOCs (Massive Open Online Courses) wie auf openHPI verwendet wird. Sie ermöglicht es Lernenden, Code direkt in ihrem Browser zu schreiben, auszuführen und zu testen, ohne eine Entwicklungsumgebung einrichten zu müssen. Zu den Funktionen gehören Syntax-Hervorhebung, serverseitige Code-Ausführung und automatisiertes Feedback durch Unit-Tests. Zusätzlich können Lernende kontextbezogene Fragen stellen, was eine kollaborative Lernumgebung fördert. 
diff --git a/content/sources.asciidoc b/content/sources.asciidoc
new file mode 100644
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+
+bibliography::[]
diff --git a/main.asciidoc b/main.asciidoc
index 45e4df8..0847201 100644
--- a/main.asciidoc
+++ b/main.asciidoc
@@ -3,6 +3,7 @@
 :toc-title: Table of Contents
 :sectnums: 
 :toclevels: 2
+:bibtex-file: bibliography/CodeContender.bib
 :data-uri:
 ifndef::imagesdir[:imagesdir: media]
 ifndef::includedir[:includedir: content]
@@ -118,4 +119,8 @@ include::{includedir}/edX.asciidoc[]
 
 === edX Kubernetes Deployment ===
 
-include::{includedir}/edX-k8s.asciidoc[]
\ No newline at end of file
+include::{includedir}/edX-k8s.asciidoc[]
+
+== Sources ==
+
+include::{includedir}/sources.asciidoc[]