1. Sur une équation diophantienne;Apéry;C. R. Acad. Sci. Paris Sér. A,1960
2. On integers for which the sum of divisors is the square of the squarefree core;Broughan;J. Integer Seq.,2012
3. On odd perfect numbers;Chen;Bull. Aust. Math. Soc.,2012
4. Unsolved Problems in Number Theory;Guy,2004
5. On numbers n for which the prime factors of σ(n) are among the prime factors of n;Luca;Results Math.,2004