Light-quarkonium spectra and orbital-angular-momentum decomposition in a Bethe–Salpeter-equation approachT. Hilger, M. Gómez-Rocha and A. KrassniggEur. Phys. J. C, 77 9 (2017) 625DOI: https://doi.org/10.1140/epjc/s10052-017-5163-4