1. On the uniform distribution of certain sequences involving the Euler totient function and the sum of divisors function;De Koninck;Ann. Univ. Sci. Bp. Rolando Eötvös Nomin., Sect. Comput.,2015
2. On pseudoprimes and Carmichael numbers;Erdös;Publ. Math. (Debr.),1956
3. Common values of the arithmetic functions ϕ and σ;Ford;Bull. Lond. Math. Soc.,2010
4. An Introduction to the Theory of Numbers;Hardy,2008
5. Smooth values of the iterates of the Euler phi-function;Lamzouri;Can. J. Math.,2007