@article{AIHPA_1986__45_2_117_0,
     author = {Yngvason, Jakob},
     title = {Invariant states on {Borchers'} tensor algebra},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {117--145},
     publisher = {Gauthier-Villars},
     volume = {45},
     number = {2},
     year = {1986},
     mrnumber = {866912},
     zbl = {0639.46067},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1986__45_2_117_0/}
}