--- a/ProgTutorial/document/root.bib	Fri May 08 17:21:20 2009 +0200
+++ b/ProgTutorial/document/root.bib	Sat May 09 03:11:36 2009 +0200
@@ -135,4 +135,13 @@
   series    = {Lecture Notes in Computer Science},
   volume    = {78},
   year      = {1979}
-}
\ No newline at end of file
+}
+
+@Article{Oppen80,
+  author = 	 {D.~C.~Oppen},
+  title = 	 {Pretty Printing},
+  journal = 	 {ACM Transactions on Programming Languages and Systems},
+  year = 	 {1980},
+  pages = 	 {465--483}
+}
+