@article{DAN_1963_148_4_a18,
     author = {Liu Yi-chen and I. T. Todorov},
     title = {Integral representation of vertex part in perturbation theory},
     journal = {Doklady Akademii Nauk},
     pages = {806--809},
     publisher = {mathdoc},
     volume = {148},
     number = {4},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_148_4_a18/}
}