diff --git a/kkkk.pdf b/kkkk.pdf
index 5c3da05..c4af05a 100644
Binary files a/kkkk.pdf and b/kkkk.pdf differ
diff --git a/kkkk.tex b/kkkk.tex
index 7fce74a..8cb4027 100644
--- a/kkkk.tex
+++ b/kkkk.tex
@@ -1,6 +1,6 @@
 \documentclass[twoside,12pt,a4paper,english]{book}
 
-%\includeonly{luku03}
+%\includeonly{luku04}
 
 \usepackage[english]{babel}
 \usepackage[utf8]{inputenc}
@@ -76,7 +76,7 @@
 \include{luku01}
 \include{luku02}
 \include{luku03}
-% \include{luku04}
+\include{luku04}
 % \include{luku05}
 % \include{luku06}
 % \include{luku07}
diff --git a/luku04.tex b/luku04.tex
index 7d8a1d4..b61a399 100644
--- a/luku04.tex
+++ b/luku04.tex
@@ -478,7 +478,7 @@ the element nearest to $x$ is either the
 element that corresponds to $a$ or the previous element.
 \end{samepage}
 
-\section{Other data structures}
+\section{Other structures}
 
 \subsubsection{Bitset}