Żaba, Jerzy, and Krzysztof Gaidzik. “The Ngorongoro Crater As the Biggest Geotouristic Attraction of the Gregory Rift (Northern Tanzania, Africa) – Geographical Setting”. Geotourism/Geoturystyka, no. 24-25 ():3. https://doi.org/10.7494/geotour.2011.24-25.3.