I'm looking at a book on meteor calculations involving at two earth stations, A and B. The computations for A are given, and the same for B. I would like to know a reference for equations 12, 13, and 14. Even a derivation. I find figure 4 a bit puzzling. The text uses lower case phi, a vertical line with a circle in the middle, but the figure shows what is perhaps a capital phi. A looping curve. I'm guessing this is meant to be former symbol, vertical + circle, Secondly, it looks like the x,y,z axes for the topo system should be labeled with a prime on x,y,z. Thirdly, the two phi's look like they should have the primes swapped. Comments on my remarks?