@article{TRSPY_1965_79_a3,
     author = {A. M. Kagan},
     title = {Sufficient systems},
     journal = {Informatics and Automation},
     pages = {17--23},
     publisher = {mathdoc},
     volume = {79},
     year = {1965},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1965_79_a3/}
}