By X-ray difraction. This is a fairly new technique and there's not much literature on it. However, it's the best residual stress measuring method developed so far.
Apart from the bibligraphic research that you may do on recently published books, you can acess www.rigaku.com
Rigaku is a Japanese manufacturer who's possibly the best specialist in the world on x-ray difraction. Also, find out if they have a representative near you and get in touch with him to have a more complete opinion.
Giovanni S. Crisi
Sao Paulo - Brazil