diff --git a/doc/report/appendix.tex b/doc/report/appendix.tex
index 55926b8cf3b4cbaaca31a345941589dff738f958..5941abc486c7d4b943518f84b097a753143dd68b 100644
--- a/doc/report/appendix.tex
+++ b/doc/report/appendix.tex
@@ -4,7 +4,7 @@ Only a subset of the upper level ontology are actually taken
 advantage of in the existing Coq and Isabelle exports. This
 section lists which predicates are used and wich are not.
 
-\subsection*{ULO Predicates used in the Isabelle Exports}
+\subsection*{ULO Predicates used in the Isabelle Exports~\cite{uloisabelle}}
 
 \begin{flushleft}
     \texttt{check-time} \texttt{defines} \texttt{definition}
@@ -19,7 +19,7 @@ section lists which predicates are used and wich are not.
     \texttt{unimportant} \texttt{universe} \texttt{uses}
 \end{flushleft}
 
-\subsection*{ULO predicates \emph{not} used in the Isabelle exports.}
+\subsection*{ULO Predicates \emph{not} used in the Isabelle Exports~\cite{uloisabelle}}
 
 \begin{flushleft}
     \texttt{action-times} \texttt{aligned-with}
@@ -48,7 +48,7 @@ section lists which predicates are used and wich are not.
     \texttt{uses-implementation} \texttt{uses-interface}
 \end{flushleft}
 
-\subsection*{ULO predicates used in the Coq exports.}\label{fig:used}
+\subsection*{ULO Predicates used in the Coq Exports~\cite{ulocoq}}\label{fig:used}
 
 \begin{flushleft}
     \texttt{axiom} \texttt{definition}
@@ -61,7 +61,7 @@ section lists which predicates are used and wich are not.
     \texttt{uses}
 \end{flushleft}
 
-\subsection*{ULO predicates \emph{not} used in the Coq exports.}\label{fig:used}
+\subsection*{ULO Predicates \emph{not} used in the Coq Exports~\cite{ulocoq}}\label{fig:used}
 
 \begin{flushleft}
     \texttt{action-times} \texttt{aligned-with}