@article{AIHPA_1980__33_4_395_0,
     author = {Pul\`e, J. V.},
     title = {Positive maps of the {CCR} algebra with a finite number of non-zero truncated functions},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {395--408},
     publisher = {Gauthier-Villars},
     volume = {33},
     number = {4},
     year = {1980},
     mrnumber = {605199},
     zbl = {0471.46039},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1980__33_4_395_0/}
}