Critical Review Of Quark Gluon Plasma Signals
  Compelling evidence for a new form of matter has been claimed to be formed in Pb+Pb collisions at SPS. We critically review two suggested signatures for this new state of matter: First the suppression of the J/$\Psi$, which should be strongly suppressed in the QGP by two different mechanisms, the color-screening and the QCD-photoeffect. Secondly the measured particle, in particular strange hadronic, ratios might signal the freeze-out from a quark-gluon phase. 
D. Zschiesche, L. Gerland, S. Schramm, J. Schaffner-Bielich, H.   Stoecker, W. Greiner