CHATTERJEE, B.; BHATTACHARYA, D. A Low Frequency Helical Antenna for Sub Surface Communication. Defence Science Journal, [S. l.], v. 17, n. 3, p. 125–134, 2014. DOI: 10.14429/dsj.17.7382. Disponível em: https://publications.drdo.gov.in/ojs/index.php/dsj/article/view/7382. Acesso em: 1 jul. 2025.