diff --git a/inputs/tutorial_12b.tex b/inputs/tutorial_12b.tex
index acf7793..16e8c6e 100644
--- a/inputs/tutorial_12b.tex
+++ b/inputs/tutorial_12b.tex
@@ -20,9 +20,8 @@ The skew shift flow is not equicontinuous:
 
 
 
-\subsection{Sheet 11}
 
-We did \yaref{fact:isometriciffequicontinuous}.
+\begin{refproof}{fact:isometriciffequicontinuous}.
 
 $d$ and $d'(x,y) \coloneqq  \sup_{t \in T} d(tx,ty)$
 induce the same topology.
@@ -32,3 +31,4 @@ $\tau \subseteq  \tau'$ easy,
 $\tau' \subseteq \tau'$ : use equicontinuity.
 
 
+\end{refproof}