@article{SJIM_2006_9_1_a11,
     author = {I. A. Firdman},
     title = {Algebraic classification of physical structures with a~zero. {II.~Topological} aspects},
     journal = {Sibirskij \v{z}urnal industrialʹnoj matematiki},
     pages = {135--146},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJIM_2006_9_1_a11/}
}