@article{MZM_1975_17_5_a8,
     author = {D. V. Prokhorov},
     title = {A~generalization of the {Christoffel{\textendash}Schwartz} formula},
     journal = {Matemati\v{c}eskie zametki},
     pages = {749--756},
     year = {1975},
     volume = {17},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1975_17_5_a8/}
}