@article{TMF_1971_6_2_a7,
     author = {A. M. Pyzh'yanov},
     title = {Estimate of~the~perturbation of~the~eigenvalues of~a~two-particle {Schr\"{o}dinger} operator with a~hard-core potential},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {225--229},
     publisher = {mathdoc},
     volume = {6},
     number = {2},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1971_6_2_a7/}
}