[tmiku]

I like letter-slash-letter abbreviations but I've never run into c/f before. What does it mean? Do you remember where you first picked it up?

[ggm]

It's a misuse. CF no slash "compare" in backpieces, references &c. C/F appears to mean something in pre spreadsheet accounting but I did not study accounting at uni, so where I got the idea it needs a slash is beyond me.