Arithmetic functions associated with the infinitary divisors of an integer. Cohen, Graeme L.; Hagis, Peter jun. — 1993 International Journal of Mathematics and Mathematical Sciences
Iterating the sum-of-divisors function. Cohen, Graeme L.; te Riele, Herman J.J. — 1996 Experimental Mathematics
On perfect totient numbers. Iannucci, Douglas E.; Deng, Moujie; Cohen, Graeme L. — 2003 Journal of Integer Sequences [electronic only]