@article{TRSPY_1983_159_a10,
     author = {M. R. Sayapova and D. R. Yafaev},
     title = {The evolution operator for time-dependent potentials of zero radius},
     journal = {Informatics and Automation},
     pages = {167--174},
     publisher = {mathdoc},
     volume = {159},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1983_159_a10/}
}