@article{AL_2006_45_6_a2,
     author = {E. I. Bunina and A. V. Mikhalev},
     title = {Elementary properties of categories of acts over monoids},
     journal = {Algebra i logika},
     pages = {687--709},
     publisher = {mathdoc},
     volume = {45},
     number = {6},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2006_45_6_a2/}
}