@article{01317743,
title = {A minimax principle for eigenvalues in spectral gaps: Dirac operators with Coulomb potentials.},
journal = {Documenta Mathematica},
volume = {4},
year = {1999},
pages = {275-283},
zbl = {1115.47300},
language = {en},
url = {http://dml.mathdoc.fr/item/01317743}
}
Griesemer, Marcel; Lewis, Roger T.; Siedentop, Heinz. A minimax principle for eigenvalues in spectral gaps: Dirac operators with Coulomb potentials.. Documenta Mathematica, Tome 4 (1999) pp. 275-283. http://gdmltest.u-ga.fr/item/01317743/