diff --git a/org.rodinp.handbook.feature/latex/reference-01.tex b/org.rodinp.handbook.feature/latex/reference-01.tex
index 82dc30761f8269b8dfe9b76cf225d7f4aaf2fc38..488324891fd782eb4c7749a7b59dc8f4f1690778 100644
--- a/org.rodinp.handbook.feature/latex/reference-01.tex
+++ b/org.rodinp.handbook.feature/latex/reference-01.tex
@@ -728,7 +728,7 @@ This window allows the user to keep track of recently manipulated (i.e. used, re
 
 Operations similar to those in the \textsf{Selected Hypotheses} and \textsf{Search Hypotheses} views are also available for the cached hypotheses. It is possible to remove, select, and start a proof by contradiction (\icon{rodin/falsify_prover.png}) in the \textsf{Cache Hypotheses} view as well. Interactive proof steps (e.g., rewriting) can also be carried out in the \textsf{Cache Hypotheses} view.
 
-\subsection{The Type Environment View}
+\subsubsection{The Type Environment View}
 
 \begin{figure}[!ht]
 \begin{center}