IYER, H. M.; NANDA, J. N. Selection of Optimum Frequency for Sonar Echoes From Under Water Targets. Defence Science Journal, [S. l.], v. 8, n. 1, p. 1–4, 2014. DOI: 10.14429/dsj.8.7573. Disponível em: https://publications.drdo.gov.in/ojs/index.php/dsj/article/view/7573. Acesso em: 16 jun. 2025.