diff --git a/Doc/lib/libgettext.tex b/Doc/lib/libgettext.tex
index 5c7c6b9..6aee255 100644
--- a/Doc/lib/libgettext.tex
+++ b/Doc/lib/libgettext.tex
@@ -102,9 +102,9 @@
 return \var{plural} otherwise.
 
 The Plural formula is taken from the catalog header. It is a C or
-Python expression that has a free variable n; the expression evaluates
+Python expression that has a free variable \var{n}; the expression evaluates
 to the index of the plural in the catalog. See the GNU gettext
-documentation for the precise syntax to be used in .po files, and the
+documentation for the precise syntax to be used in \file{.po} files and the
 formulas for a variety of languages.
 
 \versionadded{2.3}