レスターの定理
↑ Lester, June A. (1997), “Triangles. III. Complex triangle functions”, Aequationes Mathematicae 53 (1–2): 4–35, doi:10.1007/BF02215963, MR1436263
↑ Kimberling, Clark (1996), “Lester circle”, The Mathematics Teacher 89 (1): 26, JSTOR 27969621, https://jstor.org/stable/27969621
↑ Shail, Ron (2001), “A proof of Lester's theorem”, The Mathematical Gazette 85 (503): 226–232, doi:10.2307/3622007, JSTOR 3622007, https://jstor.org/stable/3622007
↑ Rigby, John (2003), “A simple proof of Lester's theorem”, The Mathematical Gazette 87 (510): 444–452, doi:10.