Babu, C G Karthick; Sankaranarayanan, A., 2021, On An Estimate Of A Certain Non-Linear Exponential Sum, Indian Journal Of Pure And Applied Mathematics, 53, 1, pp. 1-9, 10.1007/s13226-021-00003-0.
Granville, Andrew; RamarĂŠ, Olivier, 1996, Explicit Bounds On Exponential Sums And The Scarcity Of Squarefree Binomial Coefficients, Mathematika, 43, 1, pp. 73-107, 10.1112/s0025579300011608.
Guy, Richard K., 2004, Divisibility, Unsolved Problems In Number Theory, pp. 71-158, 10.1007/978-0-387-26677-0_3.
Narkiewicz, WĹadysĹaw, 2012, The Thirties, Springer Monographs In Mathematics, pp. 195-273, 10.1007/978-0-85729-532-3_4.