@article{AIHPA_1997__67_1_29_0,
     author = {Ben-Artzi, Matania and Nemirovsky, Jonathan},
     title = {Remarks on relativistic {Schr\"odinger} operators and their extensions},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {29--39},
     publisher = {Gauthier-Villars},
     volume = {67},
     number = {1},
     year = {1997},
     mrnumber = {1463003},
     zbl = {0885.35135},
     language = {en},
     url = {http://archive.numdam.org/item/AIHPA_1997__67_1_29_0/}
}