Update README.md

Interesting and useful for researchers.

README.md

@@ -92,3 +92,14 @@ You can use the Google group for improvements, feature requests, comments
 
     http://www.arangodb.org/connect
 
+
+Citing ArangoDB
+---------------
+Please kindly cite ArangoDB in your publications if it helps your research:
+
+@misc{Jan13ArangoDB,
+   Author = {Jan Steeman, Michael Hackstein},
+   Title = { {ArangoDB}: An Open Source multi-purpose database supporting flexible data models for documents, graphs, and key-values.},
+   Year  = {2013},
+   Howpublished = {\url{http://arangodb.org/}
+}