@article{DE_1977_13_11_a4,
     author = {\`E. I. Grudo},
     title = {The representation of the fundamental matrices of completely integrable linear homogeneous {Pfaffian} systems with an irregular singular point},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1940--1950},
     publisher = {mathdoc},
     volume = {13},
     number = {11},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1977_13_11_a4/}
}