@article{DAN_1978_239_5_a19,
     author = {V. P. Kalashnikov},
     title = {A new approach to the calculation of the time correlation functions and the {Wick's} generalized theorem},
     journal = {Doklady Akademii Nauk},
     pages = {1089--1092},
     publisher = {mathdoc},
     volume = {239},
     number = {5},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_239_5_a19/}
}