Kachalin, Igor, Oleksandr Liashchuk, and Stanka Šebela. “Periodical Measurements of VLF Radio Signals and Noise Sounds in Črna Jama (Postojnska Jama)”. Acta Carsologica 46, no. 1 (July 4, 2017). Accessed March 28, 2024. https://ojs.zrc-sazu.si/carsologica/article/view/1950.