@article{FAA_1988_22_1_a2,
     author = {P. G. Grinevich and S. P. Novikov},
     title = {Two-dimensional ``inverse scattering problem'' for negative energies and generalized-analytic functions. {I.} {Energies} below the ground state},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {23--33},
     publisher = {mathdoc},
     volume = {22},
     number = {1},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1988_22_1_a2/}
}