--- a/Journal/document/root.bib	Wed Sep 07 18:17:56 2011 +0000
+++ b/Journal/document/root.bib	Thu Sep 08 15:08:02 2011 +0000
@@ -1,5 +1,15 @@
 
 
+@incollection{Nipkow11,
+  author =       {T.~Nipkow},
+  title =        {{G}auss-{J}ordan {E}limination for {M}atrices {R}epresented as {F}unctions},
+  booktitle =    {The Archive of Formal Proofs},
+  editor =       {G.~Klein and T.~Nipkow and L.~Paulson},
+  publisher =    {\url{http://afp.sourceforge.net/entries/Gauss-Jordan-Elim-Fun.shtml}},
+  year =         2011,
+  note =         {Formal proof development},
+  ISSN =         {2150-914x}
+}
 
 @Article{Haines69,
   author = 	 {L.~H.~Haines},