Υ (9.46 GeV) and the gluon discovery (a critical recollection of PLUTO results) Bruno R. Stella and Hans-Jürgen Meyer Eur. Phys. J. H, 36 2 (2011) 203-243 Published online: 21 October 2011 DOI: 10.1140/epjh/e2011-10029-3