@article{DE_1986_22_11_a16,
     author = {A. Yanushauskas},
     title = {On non-strongly-elliptic systems of second-order partial differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1984--1990},
     publisher = {mathdoc},
     volume = {22},
     number = {11},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_11_a16/}
}