diff --git a/Doc/ref/ref5.tex b/Doc/ref/ref5.tex
index 6e4207f..462548f 100644
--- a/Doc/ref/ref5.tex
+++ b/Doc/ref/ref5.tex
@@ -780,8 +780,9 @@
 In addition to performing the modulo operation on numbers, the \code{\%}
 operator is also overloaded by string and unicode objects to perform
 string formatting (also known as interpolation). The syntax for string
-formatting is described in the Python Library Reference, section
-``Sequence Types''.
+formatting is described in the
+\citetitle[../lib/typesseq-strings.html]{Python Library Reference},
+section ``Sequence Types''.
 
 \deprecated{2.3}{The floor division operator, the modulo operator,
 and the \function{divmod()} function are no longer defined for complex