diff --git a/chapter19.tex b/chapter19.tex
index 6b00034..29383bb 100644
--- a/chapter19.tex
+++ b/chapter19.tex
@@ -588,9 +588,9 @@ A \key{knight's tour} is a sequence of moves
 of a knight on an $n \times n$ chessboard
 following the rules of chess such that the knight
 visits each square exactly once.
-The tour is \key{closed} if the knight finally
+A tour is \emph{closed} if the knight finally
 returns to the starting square and
-otherwise the tour is \key{open}.
+otherwise it is \emph{open}.
 
 For example, here is an open knight's tour on a $5 \times 5$ board: