Newton polyhedra and the degree of the L-function associated to an exponential sum. A. Adolphson, S. Sperber (1987) Inventiones mathematicae
Nombres presque premiers et sommes trigonométriques Jean-Marc Deshouillers (1970/1971) Séminaire de théorie des nombres de Bordeaux
Nonlinear exponential twists of the Liouville function Qingfeng Sun (2011) Open Mathematics Let λ(n) be the Liouville function. We find a nontrivial upper bound for the sum ∑ X ⩽ n ⩽ 2 X λ ( n ) e 2 π i α n , 0 ≠ α ∈ ℝ The main tool we use is Vaughan’s identity for λ(n).