diff --git a/Doc/lib/libposix.tex b/Doc/lib/libposix.tex
index 6b7a312..7edd93e 100644
--- a/Doc/lib/libposix.tex
+++ b/Doc/lib/libposix.tex
@@ -417,7 +417,7 @@
 the \code{unlink} name is its traditional \UNIX{} name.
 \end{funcdesc}
 
-\begin{funcdesc}{utime}{path\, \(atime\, mtime\)}
+\begin{funcdesc}{utime}{path\, {\rm (}atime, mtime{\rm )}}
 Set the access and modified time of the file to the given values.
 (The second argument is a tuple of two items.)
 \end{funcdesc}