Zdroje
http://blog.dedoles.sk/jaskyna-z-ineho-sveta/http://rusemb.sk/svk/informacie-o-rusku/http://wol.jw.org/pl/wol/d/r38/lp-v/102007085http://dromedar.topky.sk/cl/1000020/762205/Na-Kamcatku-za-lososmi--
gejzirmi-a-cinnymi-sopkamihttp://magazin.atlas.sk/techmag/reportaz-skryty-svet-pod-moskvou/818861.html