Pseudoscalar Vertex, Goldstone Boson and Quark Masses on the Lattice
  We analyse the Structure Function collaboration data on the quark pseudoscalar vertex and extract the Goldstone boson pole contribution, in 1/p2. The strength of the pole is found to be quite large at presently accessible scales. We draw the important consequences of this finding for the various definitions of quark masses, and point out potential problems with the operator product expansion. 
J.R. Cudell, A. Le Yaouanc and C. Pittori