Index: doc/theses/fangren_yu_MMath/background.tex
===================================================================
--- doc/theses/fangren_yu_MMath/background.tex	(revision 18a7dcf12cb8d61e7214bb8aab1e4fe441d56c0e)
+++ doc/theses/fangren_yu_MMath/background.tex	(revision 0497b6ba3fd2570c5022f91577f43565dbbd1758)
@@ -1,4 +1,5 @@
 \chapter{Background}
 
+\cite{Melo17} \cite{Odersky01} \cite{Pierce00}
 
 \section{Polymorphism}