How to determine a typeface's origin and whether I have a license?

I am currently working on the cover of a book.

I'd really like to include the typeface Rockwell Extra Bold which is installed on my system. However Rockwell Extra Bold seems not to be installed through OSX nor through the Adobe Suite (CS4).

Is there a way to find out how this typeface ended up on my system and thus whether I am allowed to use it in the context of a printed book?

I definitely did not download any typeface by hand to this system so it must have come through some software I legally purchased and installed.

I do wan't to be sure though before using it in such a context.

Thank you very much for any advice, I appreciate it very much!

Have a nice day! Tom