@article{DAN_1957_116_4_a7,
     author = {E. S. Lyapin},
     title = {On the existence and uniqueness of a solution to the general type of equation in connection with reversibility 
},
     journal = {Doklady Akademii Nauk},
     pages = {552--555},
     publisher = {mathdoc},
     volume = {116},
     number = {4},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_116_4_a7/}
}