On pion correction to quark mass in next-leading order of mean-field   expansion in NJL model
  The correction to quark mass are calculated in Nambu-Jona-Lasinio model with 4-dimensional cutoff regularization and with dimensional-analytical regularization in the next-to-leading order of mean-field expansion. The analytical calculations show that the pion correction to quark mass is equal to zero. Comparing the results in both regularizations one can signify that the zero value of the pion correction to quark mass is the regularization-independent fact of Nambu-Jona-Lasinio model. 
R.G. Jafarov