Looking for old Sun (Sparc) compiler

I am attempting to resurrect some software that was built using
a development tool that was in turn dependent on a specific
Sun (Sparc) compiler -- SunPro C 4.2 running on Solaris 2.6.

I have Solaris 2.6, and Sun makes licenses available on their
Web site for SunPro C 4.2, but I have failed so far to locate
a source for the compiler itself.

Does anybody on this mailing list have an idea where I could
locate (for purchase, if necessary) a copy of this
long-discontinued Sun software?

Thanks for any help you can provide.