@article{DE_1987_23_10_a8,
     author = {I. A. Bikchantaev},
     title = {Differential boundary value problems for first-order elliptic systems on {Riemann} surfaces},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1725--1736},
     publisher = {mathdoc},
     volume = {23},
     number = {10},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1987_23_10_a8/}
}