@article{DAN_1957_116_6_a7,
     author = {Yu. I. Cherskii},
     title = {The reduction of mixed boundary problems to the {Riemannian} boundary problem},
     journal = {Doklady Akademii Nauk},
     pages = {927--929},
     year = {1957},
     volume = {116},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_116_6_a7/}
}