Wongsan, R., P. Khamsalee, A. Wannakomol, P. Kumsawat, A. Srikaew, and A. Jantaupalee. “A Study on Radio Wave Propagation in Chiang Dao Cave”. Journal of Digital Communications, vol. 6, no. 6, Nov. 2022, pp. 123-47, https://so04.tci-thaijo.org/index.php/NBTC_Journal/article/view/256861.