@article{TMF_2011_168_3_a12,
     author = {N. M. Plakida},
     title = {The~two-time {Green's} function and the~diagram technique},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {518--535},
     publisher = {mathdoc},
     volume = {168},
     number = {3},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2011_168_3_a12/}
}