Low Cost Heart Rate Monitor Using Led-Led Sensor. Al-Khwarizmi Engineering Journal, [S. l.], v. 5, n. 3, p. 23–27, 2009. Disponível em: https://www.alkej.uobaghdad.edu.iq/index.php/alkej/article/view/568. Acesso em: 30 apr. 2025.