Calculation of infrared-divergent Feynman diagrams with zero mass threshold J. Fleischer, V.A. Smirnov, A. Frink, J. Körner, D. Kreimer, K. Schilcher and J.B. TauskEur. Phys. J. C, 2 4 (1998) 747-756DOI: https://doi.org/epjc/v2/p747(epjc721)