Relativistic quark-antiquark potential and heavy quarkonium mass spectra
  A general approach to accounting for retardation effects in the long-range (confining) part of the quark-antiquark potential is presented. The charmonium and bottomonium mass spectra are calculated with the systematic account of relativistic and retardation effects and the one-loop radiative corrections. A good fit to available experimental data on the mass spectra is obtained. 
D. Ebert, R. N. Faustov, V. O. Galkin