ヘレン・ケイン
↑ The history of us: Tombstone tourism connects visitors to Long Island's past Newsday 2019年10月18日
↑ Birth certificate, born 4 Aug 1904
↑ Find-a-Grave
↑ U.S, Census, 1910, NYC.
↑ Mitchell, Glenn (2003). The Marx Brothers Encyclopedia. London: Reynolds & Hearn. pp. 162. ISBN 1-905287-11-9
↑ IP Due Diligence: “Boop-Oop-A-Doop” IndieClear