Note on Closed-Form Expressions for Irreducible Loop Integrals
  We provide a new analysis of the irreducible loop integrals first considered in a 2003 paper of Wu. Using convergence ideas from probability, we produce conditions on the regulator masses so that the integrals have well-defined limits in the limit required by the regularisation technique; we then derive closed-form expressions for the regularised forms of these integrals in terms of incomplete Gamma-functions. 
Richard Chapling
hep-th math.CA math.PR