editing
approved
editing
approved
J. J. O'Connor and E. F. Robertson, <a href="https://web.archive.org/web/20191031160158/http://www-history.mcsmathshistory.st-andandrews.ac.uk/Biographies/Van_Ceulen.html/">Ludolph Van Ceulen</a>.
reviewed
editing
proposed
reviewed
editing
proposed
J. J. O'Connor and E. F. Robertson, <a href="https://web.archive.org/web/20191031160158/http [Broken link]
reviewed
editing
proposed
reviewed
editing
proposed
J. J. O'Connor and E. F. Robertson, <a href="http://www-history.mcs.st-and.ac.uk/Biographies/Van_Ceulen.html">Ludolph Van Ceulen</a>. [Broken link]
David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 55.
approved
editing
proposed
approved