Path integrals in polar field variables in QFT E. N. Argyres, C. G. Papadopoulos, M. T. M. van Kessel and R. H. P. Kleiss Eur. Phys. J. C, 61 3 (2009) 495-518 Published online: 08 April 2009 DOI: 10.1140/epjc/s10052-009-0998-y