diff --git a/Bookshelf/Apostol.tex b/Bookshelf/Apostol.tex
index 27122aa..16471d7 100644
--- a/Bookshelf/Apostol.tex
+++ b/Bookshelf/Apostol.tex
@@ -2578,7 +2578,7 @@ The function $f$ is \nameref{sec:def-integrable} on $[a, b]$ if and only if
 \chapter{The Area of an Ordinate Set Expressed as an Interval}%
 \label{chap:area-ordinate-set-expressed-interval}
 
-\section{Theorem 1.10}%
+\section{\partial{Theorem 1.10}}%
 \label{sec:theorem-1.10}
 
 Let $f$ be a nonnegative function, \nameref{sec:def-integrable} on an interval
@@ -2601,7 +2601,7 @@ Then $Q$ is measurable and its area is equal to the integral
 
 \end{proof}
 
-\section{Theorem 1.11}%
+\section{\partial{Theorem 1.11}}%
 \label{sec:theorem-1.11}
 
 Let $f$ be a nonnegative function, integrable on an interval $[a, b]$.