@article{MZM_1967_1_5_a2,
     author = {K. A. Zaretskii},
     title = {An abstract characterization of the bisemigroup of binary operations},
     journal = {Matemati\v{c}eskie zametki},
     pages = {525--530},
     year = {1967},
     volume = {1},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1967_1_5_a2/}
}