Petr Beckmann (1982). A history of p (Pi) (Fifth Edition), p.198-199: Chronological Table. USA: The Golem Press.
Petr Beckmann (1982). A history of p (Pi) (Fifth Edition), p.198-199: Chronological Table. USA: The Golem Press.
九章出版社编辑部编（1981）。数学家传奇，页50-74：「科学上常用的常数-圆周率」。台北：九章出版社。