Excellent !! online paper (pdf ) on neutrino oscillation and neutrino mass:
Neutrino oscillations By Mark Thomson Cavendish Laboratory, University of Cambridge, http://tinyurl.com/5fq46 or http://www.journals.royalsoc.ac.uk/app/home/content.asp?wasp=99eqac4qxh2kuva9lk1p&referrer=contribution&format=2&page=1&pagecount=18
