ParticleData Source Information
ParticleData is based on a wide range of sources, with enhancement at the Wolfram Research Companies by both human and algorithmic processing.
Among principal sources for ParticleData are:
Durham (UK) HEP Database Group. "HEPDATA: The Durham HEP Databases." 2009. »
Grigoriev, I. S. Handbook of Physical Quantities. 1997.
Yao, W-M, et al. and Particle Data Group. "Review of Particle Physics." Journal of Physics G: Nuclear and Particle Physics 33, no. 1, (2006): 1-1232. »