Try Fernadez-de-la-penas in pub med, he has done plenty on MTrP.

Fryer and Hodgson (2005). the effect of manual pressure release on myofascial trigger points in the upper trapezius. Journal of Bodywork and Movement therapies.

Blanco RC et al. 2006. Change in active mouth opening following a single treatmetn of latent myofascial trigger points in the masseter muscle....journal of bodywork and movement therapies.

also try of interest for you would be
Lucas et al (2004). latent trigger points: their effects in muscle activation and movement efficiency. journal of bodywork and movement therapies.

try these for starters. if you find any others please let me know especially if there are articles that report ineffective treatments. hope these help you on your way.