Varga, Peter, Jaroslav Lexa, Peter Uhlík, and Michal Rajnoha. 2015. “Characterization of Perlites from Jastrabá and Lehôtka Pod Brehmi Deposits”. Geology, Geophysics and Environment 41 (1):146. https://doi.org/10.7494/geol.2015.41.1.146.