Finding ellipses and hyperbolas tangent to two, three, or four given lines. Horwitz, Alan (2002) Southwest Journal of Pure and Applied Mathematics [electronic only]
Fixed points of rotations of n -sphere. Prabhu, Nagabhushana (1999) International Journal of Mathematics and Mathematical Sciences
Formules proposées par M. Desboves E. Barisien (1876) Nouvelles annales de mathématiques : journal des candidats aux écoles polytechnique et normale