--- a/document/root.bib	Sun Dec 30 21:18:39 2012 +0000
+++ b/document/root.bib	Sun Dec 30 22:15:54 2012 +0000
@@ -37,3 +37,9 @@
   year = 	 {2012}
 }
 
+@book{Boolos87,
+  author    = {G.~Boolos and R.~C.~Jeffrey},
+  title     = {{C}omputability and {L}ogic (2.~ed.)},
+  publisher = {Cambridge University Press},
+  year      = {1987}
+}
\ No newline at end of file