PATERSON, W. E. Elementary Trigonometry. The Journal of the Indian Mathematical Society, [S. l.], v. 5, n. 6, p. 215–215, 1913. DOI: 10.18311/jims/1913/17719. Disponível em: http://informaticsjournals.com/index.php/jims/article/view/17719. Acesso em: 28 apr. 2024.