@article{AL_2011_50_3_a5,
     author = {A. A. Stepanova and N. V. Trikashnaya},
     title = {Abelian and {Hamiltonian} varieties of groupoids},
     journal = {Algebra i logika},
     pages = {388--398},
     publisher = {mathdoc},
     volume = {50},
     number = {3},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2011_50_3_a5/}
}