@article{DE_1978_14_8_a22,
     author = {\`E. I. Grudo},
     title = {A method for lowering the order of linear differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1514--1515},
     publisher = {mathdoc},
     volume = {14},
     number = {8},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1978_14_8_a22/}
}