@article{MZM_1974_16_2_a12,
     author = {V. S. Monakhov},
     title = {The product of two groups, one of which contains a~cyclic subgroup of index $\le2$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {285--295},
     publisher = {mathdoc},
     volume = {16},
     number = {2},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1974_16_2_a12/}
}