en Vaughan, R. C.; Wooley, T. D. (), „Further improvements in Waring's problem. II. Sixth powers”, Duke Mathematical Journal, 76 (3): 683–710, doi:10.1215/S0012-7094-94-07626-6, MR1309326
en Bremner, Andrew; Guy, Richard K. (), „Unsolved Problems: A Dozen Difficult Diophantine Dilemmas”, American Mathematical Monthly, 95 (1): 31–36, doi:10.2307/2323442, JSTOR2323442, MR1541235
books.google.com
en Dowden, Richard (), „(untitled)”, Mechanics' Magazine and Journal of Science, Arts, and Manufactures, Knight and Lacey, vol. 4 nr. 88, p. 54
en Vaughan, R. C.; Wooley, T. D. (), „Further improvements in Waring's problem. II. Sixth powers”, Duke Mathematical Journal, 76 (3): 683–710, doi:10.1215/S0012-7094-94-07626-6, MR1309326
en Bremner, Andrew; Guy, Richard K. (), „Unsolved Problems: A Dozen Difficult Diophantine Dilemmas”, American Mathematical Monthly, 95 (1): 31–36, doi:10.2307/2323442, JSTOR2323442, MR1541235
en Bremner, Andrew; Guy, Richard K. (), „Unsolved Problems: A Dozen Difficult Diophantine Dilemmas”, American Mathematical Monthly, 95 (1): 31–36, doi:10.2307/2323442, JSTOR2323442, MR1541235