An unsuccessful search for fractionally charged particles with mass 2.2 GeV - Bingham, H.H.; Dickinson, M.; Diebold, R.; Koch, W.; Leith, D.W.G.; Nikolic, M.; Ronne, B.; Huson, R.; Veillet, J.J.; Musset, P. (Elsevier)
http://linkinghub.elsevier.com/retrieve/pii/0031-9163(64)90144-1
Keywords: U