@article{AL_1969_8_4_a2,
     author = {S. G. Ivanov},
     title = {Standard and dually standard elements of the lattice of subgroups},
     journal = {Algebra i logika},
     pages = {440--446},
     publisher = {mathdoc},
     volume = {8},
     number = {4},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1969_8_4_a2/}
}