@article{AIHPA_1973__19_2_105_0,
     author = {Almond, D. J.},
     title = {Time operators, position operators, dilatation transformations and virtual particles in relativistic and nonrelativistic quantum mechanics},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {105--169},
     publisher = {Gauthier-Villars},
     volume = {19},
     number = {2},
     year = {1973},
     language = {en},
     url = {http://www.numdam.org/item/AIHPA_1973__19_2_105_0/}
}