@article{8417,
  author = {L. Rosenberg and Larry Spruch},
  title = {Extremum principles for the determination of relativistic bound-state energies},
  year = {1986},
  journal = {Physical Review A},
  volume = {34},
  pages = {1720-1726},
  month = {Jan-09-1986},
  issn = {0556-2791},
  url = {http://link.aps.org/doi/10.1103/PhysRevA.34.1720},
  doi = {10.1103/PhysRevA.34.1720},
}