PERISIC, D. M.; ZORIC, A. C.; GAVRIC, Z. A Frequency Multiplier Based on Time Recursive Processing. Engineering, Technology & Applied Science Research, Greece, v. 7, n. 6, p. 2104–2108, 2017. DOI: 10.48084/etasr.1499. Disponível em: https://etasr.com/index.php/ETASR/article/view/1499. Acesso em: 17 sep. 2021.