where's the key used to check gcc-4.5.1.tar.bz2.sig

[Larry Evans]

I've downloaded:

     ftp://ftp.gnu.org/gnu/gcc/gcc-4.5.1/gcc-4.5.1.tar.bz2
     ftp://ftp.gnu.org/gnu/gcc/gcc-4.5.1/gcc-4.5.1.tar.bz2.sig

then *tried* to follow instructions here:

http://www.gnupg.org/documentation/faqs.en.html#q4.19

to check the downloaded bz2 with the bz2.sig file; however,
I there's no mention on:

   http://www.gnu.org/prep/ftp.html

of where to find the:

   vendor, organisation, or issueing person's key

mentioned in faqs.en.html#q4.19.

So, where's gnu's (or whowever create the .sig file)'s
key?

TIA.

-Larry