@article{EMJ_2012_3_1_a9,
     author = {K. N. Ospanov},
     title = {Solvability conditions for the first order elliptic systems on the plane},
     journal = {Eurasian mathematical journal},
     pages = {139--142},
     publisher = {mathdoc},
     volume = {3},
     number = {1},
     year = {2012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EMJ_2012_3_1_a9/}
}