MADHAVA, K. B. On Question 549. The Journal of the Indian Mathematical Society, [S. l.], v. 9, n. 4, p. 150–152, 1917. DOI: 10.18311/jims/1917/17612. Disponível em: https://informaticsjournals.com/index.php/jims/article/view/17612. Acesso em: 5 may. 2024.