Skupio, Rafal. “Portable XRF Spectrometer With Helium Flow As a Tool for Lithological Interpretation”. Geology, Geophysics and Environment 46, no. 4 (January 29, 2021): 315–320. Accessed November 21, 2024. https://ggae.agh.edu.pl/index.php/geol/article/view/4058.