Issue #18758: Fixed and improved cross-references.
diff --git a/Doc/library/mailbox.rst b/Doc/library/mailbox.rst
index c016564..dfd4ba7 100644
--- a/Doc/library/mailbox.rst
+++ b/Doc/library/mailbox.rst
@@ -994,7 +994,7 @@
       Set the "From " line to *from_*, which should be specified without a
       leading "From " or trailing newline. For convenience, *time_* may be
       specified and will be formatted appropriately and appended to *from_*. If
-      *time_* is specified, it should be a :class:`struct_time` instance, a
+      *time_* is specified, it should be a :class:`time.struct_time` instance, a
       tuple suitable for passing to :meth:`time.strftime`, or ``True`` (to use
       :meth:`time.gmtime`).
 
@@ -1365,7 +1365,7 @@
       Set the "From " line to *from_*, which should be specified without a
       leading "From " or trailing newline. For convenience, *time_* may be
       specified and will be formatted appropriately and appended to *from_*. If
-      *time_* is specified, it should be a :class:`struct_time` instance, a
+      *time_* is specified, it should be a :class:`time.struct_time` instance, a
       tuple suitable for passing to :meth:`time.strftime`, or ``True`` (to use
       :meth:`time.gmtime`).