증명 시도
JSTOR: Access Check
http://www.jstor.org/stable/2003098
기원
웨이백 머신 - 위키백과, 우리 모두의 백과사전
https://ko.wikipedia.org/wiki/%EC%9B%A8%EC%9D%B4%EB%B0%B1_%EB%A8%B8%EC%8B%A0https://web.archive.org/web/20071027221932/http://www.southernct.edu/~sandifer/Ed/History/Preprints/Talks/NYU%20Basel%20Problem%20Paper.PDF
https://web.archive.org/web/20071027221932/http://www.southernct.edu/~sandifer/Ed/History/Preprints/Talks/NYU%20Basel%20Problem%20Paper.PDFPage Not Found | Southern Connecticut State University
http://www.southernct.edu/~sandifer/Ed/History/Preprints/Talks/NYU%20Basel%20Problem%20Paper.PDF