@article{DE_1986_22_5_a23,
     author = {\`E. I. Grudo},
     title = {Complete integrability of linear {Pfaffian} systems and conditions for linear independence of analytic functions of several variables},
     journal = {Differencialʹnye uravneni\^a},
     pages = {891--894},
     year = {1986},
     volume = {22},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_5_a23/}
}