[2] Grabiner, J. V.:
The Changing Concept of Change: The Derivative from Fermat to Weierstrass. Mathematics Magazine, 56 (1983), 4, 195–206.
DOI 10.1080/0025570X.1983.11977043
[3] Jun, Li: Some properties of the Kepler triangle. The Mathematical Gazette, 101 (2017), 552, 494–495.
[4] Sugimoto, T.: Complex Symmetries.
[5] Strogatz, S.: Infinite powers. The story of calculus, the language of the universe. Atlantic Books, Londýn, 2020.