Event Shapes and Power Corrections in e+e- Annihilation
  The effects of the hadronisation of partons on the distribution of event shape observables are associated with corrections which are suppressed by reciprocal powers of the energy scale of the process. The correction is determined by one non-calculable parameter \alpha_0 for which an universal value of 0.5 +/- 20% is found from the investigation of the distribution of event shape observables and their mean values measured in e^+e^- annihilation. 
O. Biebel (MPI Munich)