1. H. F. Baker, A Geometrical Proof of the Theorem of a Double Six of Straight Lines, Proc. Royal Soc. A 84 (1911), p. 597.
2. H. F. Baker, The General Cubic Surface, Principles of Geometry, Vol 3, Solid Geometry, Cambridge University Press (1934), pp. 159 and 225.
3. P. Beecroft, The Concordent Circles, The Lady’s and Gentleman’s Diary, The Company of Stationers, London (1843).
4. H. S. Carslaw, The Elements of Non-Euclidean Plane Geometry and Trigonometry, Longmans, London (1916).
5. H. S. M. Coxeter, Introduction to Geometry (2
nd
ed.), Wiley, New York (1969).