See:
- Ali Yamac, Oldest Documented Caves of the World, Birkleyn Caves - https://www.academia.edu/12014280/Oldest_Documented_Caves_of_the_World_Birkleyn_Caves
- Omur Harmansah, Event, Place, Performance: Rock Reliefs and Spring Monuments in Anatolia, in: Of Rocks and Water: Towards an Archaeology of Place, Edition: 1, Chapter: 11., Oxbow Books, 2014, pp.140-168
- Berkleyn - http://www.tayproject.org/TAYages.fm$Retrieve?CagNo=4716&html=ages_detail_e.html&layout=web