Add Berkeley Electronic Press.

bibs/header.bib

@@ -68,6 +68,7 @@
 @STRING{jlp      = {Journal of Logic Programming} }
 @STRING{ieee = "IEEE" }
 @STRING{acmpress = "ACM Press" }
+@STRING{bepress  = "Berkeley Electronic Press" }
 @STRING{cacm     = "Communications of the {ACM}" }
 @STRING{jacm     = "Journal of the {ACM}" }
 @STRING{tcs      = "Theoretical Computer Science" }