Media type: E-Article Title: 3500 Contributor: Gibson, Emma M.; Leith, J. D. imprint: Informa UK Limited, 1933 Published in: The American Mathematical Monthly, 40 (1933) 7, Seite 428 Language: Not determined DOI: 10.2307/2302153 ISSN: 0002-9890 Keywords: General Mathematics Origination: Footnote: Access State: Open Access