You would do well to check out the siggraph libraries, there is a *ton* of stuff in there, and I'd check out medical anatomy books. I don't know of any specific magazines.

Back at animal we had a good selection of anatomy and movement books, understanding anatomy is indispensible for modeling truly realistic characters.
Also compiling a movement library can be a good idea, this consists of getting together video footage of different creatures moving. You take animal documentaries, movies etc. and edit all of them out into species and movement types.
You end up with (for example) a group of footage of cats running at full speed, another of gorillas walking, big cats leaping onto prey etc.
Then when you get to rigging and animating your characters you can pull out the relevant footage with ease and have a reference to how these animals move in reality, from different angles at different speeds under different lighting conditions and so on. By studying them you get to understand how they should be animated.

Also, before you pony up any cash, go to your nearest university and browse through their library, and see what you can find in the medical secction on anatomy and biomechanics/kinesiology, and look at the journals section of the university, there are an astounding amount of journals on the most esoteric of subjects and you might get lucky...