H. L. Royden. Remarks on primitive notions for elementary Euclidean and non-Euclidean plane geometry. The axiomatic method with special reference to geometry and physics, Proceedings of an International Symposium held at the University of California, Berkeley, December 26,1957-January 4, 1958, Studies in logic and the foundations of mathematics, North-Holland Publishing Company, Amsterdam1959, pp. 86–96.