diff -r f662831459de -r b550d2c6ca90 doc-src/manual.bib
--- a/doc-src/manual.bib	Wed Feb 14 10:06:12 2007 +0100
+++ b/doc-src/manual.bib	Wed Feb 14 10:06:13 2007 +0100
@@ -1507,3 +1507,8 @@
   series        = LNCS,
   volume        = 2152,
   year          = 2001}
+
+@unpublished{classes_modules,
+  title         = {ML Modules and Haskell Type Classes: A Constructive Comparison},
+  author        = {Stefan Wehr et. al.}
+}