Pentaquark Searches in Electron-Positron Annihilations and Two-Photon   Collisions at LEP
  Evidence for the production of exotic hadron states composed of five quarks (pentaquarks) has been searched for in data collected by the ALEPH, DELPHI, and L3 experiments at LEP. No significant signal is observed. Several 95% C.L. upper limits are set on the production rates of such particles. 
Stephen R. Armstrong