@article{FAA_1969_3_3_a3,
     author = {Yu. V. Egorov},
     title = {Bounds for differential operators of the first order},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {53--60},
     publisher = {mathdoc},
     volume = {3},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1969_3_3_a3/}
}