@article{AIHPA_1976__25_1_1_0,
     author = {Eckmann, J.-P. and Epstein, H. and Fr\"ohlich, J.},
     title = {Asymptotic perturbation expansion for the {S-matrix} and the definition of time ordered functions in relativistic quantum field models},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {1--34},
     publisher = {Gauthier-Villars},
     volume = {25},
     number = {1},
     year = {1976},
     mrnumber = {418716},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AIHPA_1976__25_1_1_0/}
}