References
- J. S. Mackay, Bibliography of the envelope of the Wallace line, Proceedings of the Edinburgh Mathematical Society, vol. 23, 1904–1905, pp. 80–88.
- F. Morley, Orthocentric properties of the plane n-line, Transactions of the American Mathematical Society, vol. 4, 1903, p. 1.
- Morley and Patterson, On algebraic inversive invariants, American Journal of Mathematics, vol. 52, 1930, p. 413.
- H. A. Converse, On a system of hypocycloids, Annals of Mathematics (2), vol. 5, 1903–1904, pp. 105–139.
- H. Brocard, Le trifolium, Mathesis (2), vol. 2, 1892, Supplement II.
- M. V. Jerabek, Podaire de l'hypocycloide de Steiner par rapport à un point de rebroussement, Mathesis (3), vol. 5, 1905, p. 206. See also p. 245.
- G. Loria, Spezielle Algebraische und Transzendente Ebene Kurven, 1910, vol. 1, pp. 167–170.