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@article{MZM_1976_20_5_a8, author = {L. I. Vainerman}, title = {Self-conjugacy of abstract differential operators of the hyperbolic type}, journal = {Matemati\v{c}eskie zametki}, pages = {703--708}, publisher = {mathdoc}, volume = {20}, number = {5}, year = {1976}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1976_20_5_a8/} }
L. I. Vainerman. Self-conjugacy of abstract differential operators of the hyperbolic type. Matematičeskie zametki, Tome 20 (1976) no. 5, pp. 703-708. http://geodesic.mathdoc.fr/item/MZM_1976_20_5_a8/