Update AUTHORS

Author: justinethier

AUTHORS

@@ -9,5 +9,7 @@ Contributors:
   Ricardo Lanziano <[email protected]>
 
 References:
+  Write Yourself a Scheme in 48 Hours <http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours>
   R5RS <http://www.schemers.org/Documents/Standards/R5RS/HTML/>
+  CHICKEN <http://www.call-cc.org/>
   Chibi-Scheme <http://code.google.com/p/chibi-scheme/>