Žáček, V. – Škoda, R. – Laufek, F. – Sejkora, J. – Haifler, J. (2022b): Pertoldite, trigonal GeO2, the germanium analogue of α-quartz: a new mineral from Radvanice, Czech Republic. – Journal of Geosciences 67, 3, 229-237. ISSN 1802-6222. DOI 10.3190/jgeosci.355