@article{SEMR_2017_14_a16,
     author = {H. Khass and A. R. Ashrafi and B. Bazigaran},
     title = {On the lattice of f-subgroups},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {600--613},
     publisher = {mathdoc},
     volume = {14},
     year = {2017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2017_14_a16/}
}