@article{AIHPA_1980__32_4_351_0,
     author = {Pulmannov\`a, Sylvia},
     title = {Superpositions of states and a representation theorem},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {351--360},
     publisher = {Gauthier-Villars},
     volume = {32},
     number = {4},
     year = {1980},
     mrnumber = {594634},
     zbl = {0453.03066},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1980__32_4_351_0/}
}