I recently answered a question on a site called Quora, regarding this. Quora is a site where people post questions for others to answer. It’s one of the most civil discussion sites I’ve ever seen, which is why I like it. Trolling is kept to a minimum, and active, intellectual discussion is encouraged.
Anyhow, here’s the answer:
There are tonnes of sources available for Historical European Martial Arts (HEMA) found on the web, and probably the best of these is Wiktenauer.