Lowhz,
I guess I was paraphrasing music theory, not quoting it.

I regret not having learned any but bits and pieces of music theory. Like... I never had heard of the circle of fifths in high school but I worked out a means by which to name all the (major) keys by looking at the sharps and flats. With keys that have sharps, the name is a half step above the rightmost sharp. With keys that have flats, the name is the next to rightmost flat. And you can add more description consistent with that to cover F and C, which don't fall clearly into that pattern.

But no, nothing formal.