@article{DAN_1960_133_1_a15,
     author = {O. I. Zavialov},
     title = {{\textquotedblleft}Non-physical{\textquotedblright} thresholds in the perturbation theory},
     journal = {Doklady Akademii Nauk},
     pages = {64--67},
     year = {1960},
     volume = {133},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_133_1_a15/}
}