Three-Pion Interferometry Results from Central Pb+Pb Collisions at 158 A   GeV/c
  Three-particle correlations have been measured for identified negative pions from central 158 A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source. 
WA98 Collaboration: M. M. Aggarwal, et al