@article{DAN_1966_168_5_a12,
     author = {P. A. Shvartsman},
     title = {A contribution to the theory of standard systems of differential equations of positive type with periodic coefficients},
     journal = {Doklady Akademii Nauk},
     pages = {1019--1022},
     publisher = {mathdoc},
     volume = {168},
     number = {5},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_168_5_a12/}
}