One of the first things to decide before you go looking for research material is the kinds of fight scenes you want to write. Do you want harsh and bloody with lots of realism? A focus on the mental processes and emotion? Or epic heroism with nearly impossible feats of physical prowess?
Then find books which have those scenes and read the hell out of them. When I was younger, my dad handed me a copy of Conan the Freebooter and read a passage that featured Conan riding through a battlefield. In just a single paragraph, Conan's skill was shown, his fighting style, his vast knowledge of various weapons, and his demeanor on the battlefield.
Make sure there's more to your fight scene than just the thrusts and parries, that it tells a story the same way a choreographed dance piece does, and you'll do fine.