Axanthic Compatibility

What lines of Axanthics are compatible with others?

Does SK Ax. X VPI Ax. = Axanthic? How about VPI X Joliff? etc...

I know that VPI and Joliff are incompatible (produce double hets when bred together).

I don't know about the others though, sorry.

Matter of fact, I'd be real interested to know if Joliff is compatible with anything other than more Joliffs, since it can be tough to find Joliff axanthic stuff ...