@article{AIHPA_1981__34_3_309_0,
     author = {Br\"uning, Erwin},
     title = {The $n$-field-irreducible part of a $n$-point functional},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {309--328},
     publisher = {Gauthier-Villars},
     volume = {34},
     number = {3},
     year = {1981},
     mrnumber = {612220},
     zbl = {0476.46059},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1981__34_3_309_0/}
}