Magnetic Moment Definition Verification/ Proof

I saw the equation here http://en.wikipedia.org/wiki/Magneti...oop_definition for the definition of the magnetic moment for a non-planar loop. Can someone tell me if there's a name for this equation [itex]m= \frac { I }{ 2 } \int { \overrightarrow { r } } \times d\overrightarrow { r }[/itex], if it's even right, and where I could find a derivation and/or proof of the equation? I've been fumbling over this for several hours now and I've gotten absolutely nowhere. I don't have any access to any texts on the matter, all I have is google and wikipedia at the moment.

Thanks

Anthony