Oops, used a \label twice - fix one of them.
diff --git a/Doc/lib/libformatter.tex b/Doc/lib/libformatter.tex
index b769350..13d0dee 100644
--- a/Doc/lib/libformatter.tex
+++ b/Doc/lib/libformatter.tex
@@ -302,7 +302,7 @@
 \end{methoddesc}
 
 
-\subsection{Writer Implementations \label{formatter-impls}}
+\subsection{Writer Implementations \label{writer-impls}}
 
 Three implementations of the writer object interface are provided as
 examples by this module.  Most applications will need to derive new