Comparison of two Minkowski-space approaches to heavy quarkonia Sofia Leitão, Yang Li, Pieter Maris, M. T. Peña, Alfred Stadler, James P. Vary and Elmar P. Biernat Eur. Phys. J. C, 77 10 (2017) 696 Published online: 23 October 2017 DOI: 10.1140/epjc/s10052-017-5248-0