Copyrights last life of the author plus 75 years, so just because the magazine is out of business does not mean that the copyrights are not enforceable. If the magazines had one time run agreements with individuals, then the owners of the magazine can not release that info to the public without permission of the copyright holder. It's as simple as that. Some people seem to think that vintage computer software and magazines should be freely available. That will never (legally) be the case.
