1. The American Mathematical Monthly,1894
2. På gjengrodde stiger, Ladder problems;Holing;Normat,1997
3. La Geometrie, (Appendix to His Paper “Discourse on the Method”);Decartes,1637
4. The Mathematical Papers of Isaac Newton;Newton,2008
5. Réflexions sur la resolution algebrique;Lagrange;Nouveaux memoires de l’Academie Royale des Sciences et Belles-Lettres de Berlin,1770