how to search for [text] in the stubject?

I'm trying to write this filter of mine which should filter all mail
carrying the string '[text]' (without '' but [] included!) in the subject.
I already tried (among other things):

* ^Subject:.*[dmca]

but the [] are always treated like part of a regular expression.

Please, if someone knows how to search for text within brackets [text] in
the Subject, mail me privately, because I am not subscribed to the procmail
list yet.

Thanks in advance!

Herman Damveld                   \|||/
                                 (o-o)
------------------------------ooO-(_)-Ooo----------
                             Make It Happen