R.S. Thorpe, O. Williams-Thorpe, D.G. Jenkins, J.S. Watson, R.A. Ixer and R.G. Thomas, 1991. The Geological Sources and Transport of the Bluestones of Stonehenge, Wiltshire, UK. Proceedings Prehistoric Society, 57, 103-157

R.Ixer. 1996 Steep Holm 'Bluestones' Current Archaeology 151, 279

R.A. Ixer, 1997. Detailed provenancing of the Stonehenge Dolerites using reflected light petrography - a return to the light. (In: Sinclair, A., Ed., Archaeological Sciences '95. Oxbow Archaeological Monograph), 64, 11-17.