@article{PFMT_2010_4_a10,
     author = {L. A. Shemetkov},
     title = {A note on $\mathfrak{X}$-local formations},
     journal = {Problemy fiziki, matematiki i tehniki},
     pages = {61--62},
     year = {2010},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PFMT_2010_4_a10/}
}