@article{AIHPA_1971__14_4_295_0,
     author = {von Westenholz, C.},
     title = {A group theoretical model for mass-splitting},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {295--308},
     publisher = {Gauthier-Villars},
     volume = {14},
     number = {4},
     year = {1971},
     mrnumber = {287822},
     zbl = {0222.20016},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1971__14_4_295_0/}
}