[LAU] FM Synthesis introductory material

Hi list! Lately I've been interested in learning FM synthesis but I haven't found any good literature on the topic. My main objective is to be able to program sounds on the hexter dx7 clone and on my OPL3 computer (running adlibtracker 2). I can surely get some basic synthetic sounds, but I'd like to understand (at least from a pragmatic point of view) the way in which the algorithms in this kind of synths allow you to approximate one or another kind of timbre. I've been told once that the dx7 had a huge potential for physical modelling, but that most musicians didn't really know how to program it. Using only analog synth common sense, I've been able to get some clavinet kind of sound, but some other sounds such as a slap bass have proven to be much more complex. I've already downloaded some patch banks for hexter, and while they are illustrative, I still don't get the choice of algorithms. Thank you so much to all of you. Have a nice one! Fede