@article{ZNSL_1997_249_a5,
     author = {M. Sh. Birman and A. B. Pushnitskii},
     title = {Discrete spectrum in the gaps of perturbed pseudorelativistic {Hamiltonian}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {102--117},
     year = {1997},
     volume = {249},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1997_249_a5/}
}