1. Archwilio - http://www.cofiadurcahcymru.org.uk/arch/dyfed/english/dyfed_interface.html
2. Benson, D.G., Evans, J.G., Williams, G.H., Darvill, T, and David, A. 1990. Excavations at Stackpole Warren, Dyfed. Proceedings of the Prehistoric Society 56, 179-245.
3. Burl, A. 1993. From Carnac to Callanish – The Prehistoric Stone Rows of Britain, Ireland and Brittany. Yale University Press, New Haven and London.
4. Cleave Books Triangle Calculating Tool - http://www.cleavebooks.co.uk/scol/calrtri.htm Coflein - http://www.coflein.gov.uk/en/quick_search/?simple_keyword=standing+stone+pair&action=site&z=0&zz=0&order_by=ASCRELEVANCE
5. Cunliffe, B. 2000. Facing the Ocean. Routledge, London.