--- a/model/prov-constraints.html	Wed Jul 18 11:55:07 2012 +0100
+++ b/model/prov-constraints.html	Wed Jul 18 14:50:59 2012 +0100
@@ -157,10 +157,10 @@
 
       var extraReferences = {
         "CHR":
-         "AUTHOR "+
-         "<a href=\"???\"><cite>TITLE</cite></a>."+
-         " PUBLISHER "+
-         " URL: <a href=\"???\">URL</a>",
+         "Thom Frühwirth "+
+         "<a        href=\"http://constraint-handling-rules.org/\"><cite>Constraint        Handling Rules</cite></a>."+
+         " Cambridge University Press "+
+         " URL: <a href=\"http://constraint-handling-rules.org/\">http://constraint-handling-rules.org/</a>",
         "CLOCK":
          "Lamport, L. "+
          "<a href=\"http://research.microsoft.com/users/lamport/pubs/time-clocks.pdf\"><cite>Time, clocks, and the ordering of events in a distributed system</cite></a>."+
@@ -173,10 +173,10 @@
          "Prentice-Hall. 1985"+
          "URL: <a href=\"http://www.usingcsp.com/cspbook.pdf\">http://www.usingcsp.com/cspbook.pdf</a>",
         "DBCONSTRAINTS":
-         " AUTHOR "+
-         " <a href=\"???\"><cite>TITLE</cite></a>."+
-         " PUBLISHER"+
-         " URL: <a href=\"???\">URL</a>",
+         " Ronald Fagin, Phokion G. Kolaitis, Renée J. Miller, and Lucian Popa "+
+         " <a href=\"http://dx.doi.org/10.1016/j.tcs.2004.10.033\"><cite>Data        exchange: Semantics and query answering</cite></a>.  Theoretical computer science 336(1):89-124 "+
+         "  Elsevier "+
+         " URL: <a href=\"http://dx.doi.org/10.1016/j.tcs.2004.10.033\">http://dx.doi.org/10.1016/j.tcs.2004.10.033</a>",
 	    "Logic":
           "W. E. Johnson"+
           "<a href=\"http://www.ditext.com/johnson/intro-3.html\"><cite>Logic: Part III</cite></a>."+