LEISCHNER, P. Polibky kružnic: Philip Beecroft. Matematika–Fyzika–Informatika, [S. l.], v. 27, n. 1, p. 1–8, 2018. Disponível em: https://mfi.upol.cz/index.php/mfi/article/view/377. Acesso em: 24 dub. 2024.