Almeida, Guilherme de. “A Simple and Intuitive Method to Determinate the Excentricity of Earth’s Orbit Around the Sun”. Caderno Brasileiro de Ensino de Física 30, no. 1 (April 17, 2013): 165–176. Accessed August 31, 2024. https://periodicos.ufsc.br/index.php/fisica/article/view/2175-7941.2013v30n1p165.