diff --git a/diff.c b/diff.c
index 1bcbbd5bb1..0f98bff46b 100644
--- a/diff.c
+++ b/diff.c
@@ -1421,8 +1421,10 @@ static const struct funcname_pattern_entry builtin_funcname_pattern[] = {
 	{ "python", "^[ \t]*((class|def)[ \t].*)$", REG_EXTENDED },
 	{ "ruby", "^[ \t]*((class|module|def)[ \t].*)$",
 	  REG_EXTENDED },
+	{ "bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$",
+	  REG_EXTENDED },
 	{ "tex",
-	  "^(\\\\((sub)*section|chapter|part)\\*{0,1}\{.*)$",
+	  "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
 	  REG_EXTENDED },
 };