SHAW, T. R.; ČUK, A. The Underground Post Offices of Postojnska jama, Slovenia, 1899 - 1945. Acta Carsologica, Ljubljana, Slovenija, v. 32, n. 1, 2016. DOI: 10.3986/ac.v32i1.374. Disponível em: https://ojs.zrc-sazu.si/carsologica/article/view/374. Acesso em: 3 may. 2024.