Media type: E-Article Title: News & Letters Contributor: Graber, James S.; Appel, Kenneth; Haken, Wolfgang; Graber, James S.; Appel, Kenneth; Haken, Wolfgang; Appel, Kenneth; Haken, Wolfgang; Fleming, Kirk; Bailey, Donald F.; Subbarao, M.V. imprint: Informa UK Limited, 1977 Published in: Mathematics Magazine Language: English DOI: 10.1080/0025570x.1977.11976642 ISSN: 0025-570X; 1930-0980 Keywords: General Mathematics Origination: Footnote: