@article{AIHPA_1978__28_1_41_0,
     author = {Kr\'ee, Paul and R\k{a}czka, Ryszard},
     title = {Kernels and symbols of operators in quantum field theory},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {41--73},
     publisher = {Gauthier-Villars},
     volume = {28},
     number = {1},
     year = {1978},
     mrnumber = {482179},
     zbl = {0386.47015},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1978__28_1_41_0/}
}