@article{DE_1991_27_6_a18,
     author = {S. R. Umarov},
     title = {An algebra of pseudodifferential operators with variable analytic symbols and the well-posedness of the corresponding equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1056--1063},
     publisher = {mathdoc},
     volume = {27},
     number = {6},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1991_27_6_a18/}
}