Wayne Miller has written a great article about the M54 here.
Robert Rule has written a great book on the pre-64 Winchester 70, the offspring of the M54. Available on Amazon for way to much. It has a nice chapter on the M54, which isn't available here.
Chuck Hawks has a nice write-up here. He also mentions the M54 in his article on the M70.
American Rifleman has a short article on the M54 leading into an article about the M70
Here's a pretty good set of photos of a factory custom M54. Even though it's a custom, all the non-obvious custom stuff is factory standard, and provides good reference. If that link is outdated, I've saved a primitive copy here.
