Single-spin asymmetries: the Trento conventions
  During the workshop "Transversity: New Developments in Nucleon Spin Structure" (ECT*, Trento, Italy, 14-18 June 2004), a series of recommendations was put forward by the participants concerning definitions and notations for describing effects of intrinsic transverse momentum of partons in semi-inclusive deep inelastic scattering. 
Alessandro Bacchetta, Umberto D'Alesio, Markus Diehl, C. Andy Miller