Addition of citations related to metamorphic testing

Lectures/L10_VnVContinued/VnVContinued.tex

@@ -458,7 +458,8 @@ constituents of compound conditions are exercised at least once
 \item \uncover<2->{List is sorted}
 \item \uncover<2->{Number of entries in file matches number of inputs}
 \item \uncover<2->{Conservation of energy or mass}
-\item \uncover<2->{Expected trends in output are observed (metamorphic testing)}
+\item \uncover<2->{Expected trends in output are observed (metamorphic testing
+    \cite{Kanewala2015, KanewalaAndBieman2013, KanewalaAndLundgren2016})}
 \item \uncover<2->{etc.}
 \ei
 \end{itemize}