@article{UZERU_2011_2_a2,
     author = {V. Zh. Dumanyan},
     title = {On compactness of a class of first order linear differential operators},
     journal = {Proceedings of the Yerevan State University. Physical and mathematical sciences},
     pages = {17--21},
     publisher = {mathdoc},
     number = {2},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UZERU_2011_2_a2/}
}