@article{MZM_1977_22_2_a5,
     author = {V. V. Pospelov},
     title = {A~family of extension operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {215--219},
     publisher = {mathdoc},
     volume = {22},
     number = {2},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1977_22_2_a5/}
}