diff -r 2fad78b479a3 -r 455411d69c12 Paper/document/root.bib
--- a/Paper/document/root.bib	Tue Feb 19 04:56:33 2013 +0000
+++ b/Paper/document/root.bib	Tue Feb 19 05:11:33 2013 +0000
@@ -74,6 +74,14 @@
   year      = {2007}
 }
 
+@book{BoolosFourth,
+  author    = {G.~Boolos and J.~P.~Burgess and R.~C.~Jeffrey},
+  title     = {{C}omputability and {L}ogic (4th~ed.)},
+  publisher = {Cambridge University Press},
+  year      = {2002}
+}
+
+
 @inproceedings{WuZhangUrban11,
   author    = {C.~Wu and X.~Zhang and C.~Urban},
   title     = {{A} {F}ormalisation of the {M}yhill-{N}erode {T}heorem based on {R}egular {E}xpressions