HARTONO, H. G.; PRAKOSO, T. W.; DALIO, D. W.; STEVEN, A. Studi Awal Keberadaan Gunung Api Purba Tulakan-Ketro, Pacitan, Jawa Timur. ReTII, [S. l.], 2017. Disponível em: https://sandbox.itny.ac.id/index.php/ReTII/article/view/267. Acesso em: 20 jul. 2025.