@article{DVMG_2011_11_2_a4,
     author = {V. E. Lopatkin},
     title = {The cohomology rings of asynchronous transition systems},
     journal = {Dalʹnevosto\v{c}nyj matemati\v{c}eskij \v{z}urnal},
     pages = {181--189},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DVMG_2011_11_2_a4/}
}