Best resource for serious Commodore 64 programming

[JohnMarson]

What is the best resource for serious Commodore 64 programming?

Assume that serious programming on the Commodore 64 is not done in BASIC V2 that ships with the Commodore 64.

I feel like most of the knowledge is tied up in old books and not available on the internet.

All that I have found online are either very beginner style introductions to Commodore 64 programming (Hello world), or arcane demo-coder hacks to take advantage of strange parts of the hardware. I haven't found a well-explained list of opcodes, memory locations for system calls, and general mid-level examples and tips.

Main portals I have found:
World of Fairlight
lemon64
C-64 Scene Database
c64web Actually hosted on a Commodore 64!

Tools I have found:
cc65 A C compiler that can target Commodore 64.

[rbernardo]

What is the best resource for serious Commodore 64 programming?

Look around the .PDF's at

http://www.bombjack.org/commodore/applications/

Truly,

[JohnMarson]

Thanks for sharing