QCD Studies and alpha_s Measurements at LEP
  The LEP experiments have measured event shapes using data taken at e+e- center-of-mass energies ranging from 91 GeV to 209 GeV. Using the final LEP event shape measurements, a combined value of the strong coupling constant alpha_s(M_Z) has been extracted. Events with photon radiation have been used to extend the measurements to lower center-of-mass energies sqrt(s') to study the running of alpha_s. Alternative alpha_s measurements using four-jet rates have also been performed. 
Stefan Soldner-Rembold