L. E. Dickson, History Of The Theory Of Numbers, pp.3-33, 1919.

E. Euclid and I. Book, Prop. 36 Available at http://wikipedia.org/wiki/File:Euclid-Elements.pdf

L. Euler, Tractatus de numerorum doctrina capita sedecim quae supersunt, Opera Omnia Series I, pp.503-575, 1849.

A. Flammenkamp, The Multiply Perfect Numbers Page

R. K. Guy, Divisors and Desires, The American Mathematical Monthly, vol.104, issue.4, pp.359-360, 1997.
DOI : 10.2307/2974586

J. Koninck, Ces Nombres qui Nous Fascinent. Ellipses English translation " Those Fascinating Numbers " published by Amer, Math. Soc, 2008.

J. Roberts, Lure of the Integers, Math. Assoc. America, p.176, 1992.

N. J. Sloane, The On-Line Encyclopedia of Integer Sequences
DOI : 10.1007/978-3-540-73086-6_12

I. Stewart and L. , Les nombres multiparfaits, Belin?Pour La Science, vol.15, pp.82-88, 2000.

D. Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, pp.135-136, 1987.

M. Zhang, A note on the equation ?(n) + ?(n) = 3 n, Sichuan Daxue Xuebao, vol.37, pp.39-40, 2000.