@article{RM_1970_25_4_a18,
     author = {G. I. \`Eskin},
     title = {Elliptic pseudodifferential equations with a~first order degeneracy},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {25},
     number = {4},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1970_25_4_a18/}
}