[sllabres]

I have seen the topic a bit late, but nevertheless:

I have learned 6502 assembler (and assembler) in general with "6502 assembly language programming by Lance A. Leventhal" (1979) [1] and "Apple Machine Language by Don Inman & Kurt Inman" (1981) [2]

For the 'internals' of the machine, I had "What's Where in the Apple: A Complete Guide to the Apple Computer by William F. Luebbert" (1985) amazon:[3]

[1] https://archive.org/details/6502-assembly-language-programmi...

[2] https://archive.org/details/a2-ml

[3] https://www.amazon.de/Whats-Where-Apple-Complete-Computer/dp...