Where to get debian iso public pgp key?

[Pat <paparsoss@gmail.com>]

Hello,
 I have downloaded the md5sums file for the iso images and gpg gives me:
 gpg: Signature made Sat 07 Apr 2007 09:17:29 PM CDT using DSA key ID 88C7C1F7
gpg: Can't check signature: public key not found

Where do I find this key for verification? It is not on https://db.debian.org/ or http://keyserver.pgp.com/vkd/GetWelcomeScreen.event