@article{AIHPA_1999__70_3_295_0,
     author = {Karpio, Andrzej},
     title = {Hilbert spaces for massless particles with nonvanishing helicities},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {295--311},
     publisher = {Gauthier-Villars},
     volume = {70},
     number = {3},
     year = {1999},
     mrnumber = {1718184},
     zbl = {0965.81030},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1999__70_3_295_0/}
}