@article{MZM_1973_14_6_a18,
     author = {Yu. A. Drozd and V. V. Kirichenko},
     title = {Letter to the editor},
     journal = {Matemati\v{c}eskie zametki},
     pages = {943},
     publisher = {mathdoc},
     volume = {14},
     number = {6},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1973_14_6_a18/}
}