Bacelar Valente, Mário. “Einstein’s Redshift Derivations: Its History from 1907 to 1921”. Circumscribere International Journal for the History of Science 22 (December 6, 2018): 1–16. Accessed December 5, 2025. https://revistas.pucsp.br/index.php/circumhc/article/view/36437.