@article{DAN_1969_189_4_a17,
     author = {D. I. Kadyrov},
     title = {Perturbation theory for {Green's} spin functions},
     journal = {Doklady Akademii Nauk},
     pages = {760--763},
     year = {1969},
     volume = {189},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_189_4_a17/}
}