TANCREDI, G. FROM 9 TO 12 AND FINALLY 8: HOW MANY PLANETS ARE AROUND THE SUN?. Latin-American Journal of Astronomy Education, São Carlos (SP), n. 4, p. 69–77, 2007. DOI: 10.37156/RELEA/2007.04.069. Disponível em: https://relea.ufscar.br/index.php/relea/article/view/100. Acesso em: 3 jul. 2024.