Friedman, Charles N. (1993). "Sums of divisors and Egyptian fractions". J. Number Theory44: 328–339. doi:10.1006/jnth.1993.1057. The result is attributed to "M. Mossinghoff at University of Texas - Austin".
Melfi, Giuseppe (2015). "On the conditional infiniteness of primitive weird numbers". Journal of Number Theory (Elsevier) 147: 508–514. doi:10.1016/j.jnt.2014.07.024.