diff --git a/hooks/subjects.pl b/hooks/subjects.pl
index 3d5ec03..b793ca4 100755
--- a/hooks/subjects.pl
+++ b/hooks/subjects.pl
@@ -97,7 +97,7 @@ sub tag_defense
     my $path;
     if ($_[3])
     {
-	if ($_[3] =~ /^(?:defenses\/)?([a-zA-Z0-9\/]+)(?:.xml)?$/) {
+	if ($_[3] =~ /^(?:defenses\/)?([a-zA-Z0-9_.\/-]+)(?:.xml)?$/) {
 	    $path = "defenses/".$1.".xml";
 	} else {
 	    $path = $_[3];