ウィレム・ド・ジッター
De Sitter, W. (1911). “On the bearing of the Principle of Relativity on Gravitational Astronomy”. Monthly Notices of the Royal Astronomical Society 71 (5): 388–415. doi:10.1093/mnras/71.5.388. hdl:2027/mdp.39015019246357.
De Sitter, W. (1913). “A proof of the constancy of the velocity of light”. Proceedings of the Royal Netherlands Academy of Arts and Sciences 15 (II): 1297–1298. Bibcode: 1913KNAB...15.1297D. “Ein astronomischer Beweis für die Konstanz der Lichtgeschwindigkeit [An astronomical proof of the constancy of the speed of light]”. Physikalische Zeitschrift 14: 429. (1913).
“On the constancy of the velocity of light”. Proceedings of the Royal Netherlands Academy of Arts and Sciences 16 (I): 395–396.