NARANIENGAR, M. T. Flexion in Polar Coordinates. The Journal of the Indian Mathematical Society, [S. l.], v. 3, n. 1, p. 26–27, 1911. DOI: 10.18311/jims/1911/17826. Disponível em: http://informaticsjournals.com/index.php/jims/article/view/17826. Acesso em: 5 may. 2024.