PSP is the major American league and they have their own format and rules which are also used by the CPS in Europe, another major event. Unless you plan on reffing stateside or in the CPS around Europe learning to be a PSP ref is going to be no use!PSP System?
Bit more information please.
Want to do the ref thing in between not playing walkon/big game.
Much better use of your time attending a CPPS clinic which will train you on the millennium format, the standard for Europe and the rest of the UK.