Bug #1057535: add link in time module to calendar.timegm().
diff --git a/Doc/lib/libtime.tex b/Doc/lib/libtime.tex
index 7a13879..6cc5e77 100644
--- a/Doc/lib/libtime.tex
+++ b/Doc/lib/libtime.tex
@@ -176,7 +176,8 @@
in UTC in which the dst flag is always zero. If \var{secs} is not
provided or \constant{None}, the current time as returned by
\function{time()} is used. Fractions of a second are ignored. See
-above for a description of the \class{struct_time} object.
+above for a description of the \class{struct_time} object. See
+\function{calendar.timegm()} for the inverse of this function.
\versionchanged[Allowed \var{secs} to be omitted]{2.1}
\versionchanged[If \var{secs} is \constant{None}, the current time is
used]{2.4}