September 12th, 2003, 2:06 pm
I think the original paper by Geman, El Karoui, and Rochet "Changes of Numeraire, Changes of Probability Measures, and Option Pricing", Journal of Applied Probability, 32, 443 - 458 (1995), is an excellent entry point to the methodology. It has a large number of examples of how the technique works, and the explanations are very clear and detailed.