@article{MZM_1967_2_6_a10,
     author = {I. I. Tugov},
     title = {A class of equivalent equations},
     journal = {Matemati\v{c}eskie zametki},
     pages = {657--663},
     publisher = {mathdoc},
     volume = {2},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1967_2_6_a10/}
}