The Dirichlet series of ζ ( s ) ζ α ( s + 1 ) f ( s + 1 ) : On an error term associated with its coefficients U. Balakrishnan, Y.-F. S. Pétermann (1996) Acta Arithmetica
The iterated Carmichael λ-function and the number of cycles of the power generator Greg Martin, Carl Pomerance (2005) Acta Arithmetica