@article{AIHPA_1979__31_1_1_0,
     author = {Demoen, Bart},
     title = {Coherent and quasi-free states},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {1--4},
     publisher = {Gauthier-Villars},
     volume = {31},
     number = {1},
     year = {1979},
     mrnumber = {557048},
     zbl = {0434.46043},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1979__31_1_1_0/}
}