@article{ADM_2010_9_1_a5,
     author = {Andrei P. Mekhovich and Nikolay N. Vorob'ev and Nikolay T. Vorob'ev},
     title = {Hall operators on the set of formations of finite groups},
     journal = {Algebra and discrete mathematics},
     pages = {72--78},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ADM_2010_9_1_a5/}
}