For many questions, especially for C-related ones, the answer seems to be found in "the standard". However, where do we find that - online?
Googling can sometimes feel futile, again especially for the C standards, since they are drowned in the flood of discussions on programming forums ;)
To get this started, since these are the ones I am searching for right now, where are there good online resources for:
C89
C99
C++03