Comparison of two Minkowski-space approaches to heavy quarkoniaSofia Leitão, Yang Li, Pieter Maris, M. T. Peña, Alfred Stadler, James P. Vary and Elmar P. BiernatEur. Phys. J. C, 77 10 (2017) 696DOI: https://doi.org/10.1140/epjc/s10052-017-5248-0