@article{TMF_1972_13_3_a3,
     author = {A. U. Klimyk},
     title = {The {Wigner{\textendash}Eckart} theorem and covariant operators},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {327--342},
     year = {1972},
     volume = {13},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1972_13_3_a3/}
}