Fox, J.G. (1962), «Experimental Evidence for the Second Postulate of Special Relativity», American Journal of Physics30 (1): 297-300, Bibcode:1962AmJPh..30..297F, doi:10.1119/1.1941992..
Alväger, T.; Farley, F. J. M.; Kjellman, J.; Wallin, L. (1964), «Test of the second postulate of special relativity in the GeV region», Physics Letters12 (3): 260-262, Bibcode:1964PhL....12..260A, doi:10.1016/0031-9163(64)91095-9..
Fox, J.G. (1962), «Experimental Evidence for the Second Postulate of Special Relativity», American Journal of Physics30 (1): 297-300, Bibcode:1962AmJPh..30..297F, doi:10.1119/1.1941992..
Alväger, T.; Farley, F. J. M.; Kjellman, J.; Wallin, L. (1964), «Test of the second postulate of special relativity in the GeV region», Physics Letters12 (3): 260-262, Bibcode:1964PhL....12..260A, doi:10.1016/0031-9163(64)91095-9..