QI, Feng; GUO, Bai-Ni. Alternative proofs for summation formulas of some trigonometric series. Global Journal of Mathematical Analysis, [S. l.], v. 5, n. 2, p. 44–46, 2017. DOI: 10.14419/gjma.v5i2.7471. Disponível em: https://sciencepubco.com/index.php/GJMA/article/view/7471.. Acesso em: 4 may. 2024.