The classical Ramanujan conjecture is given in terms of bounds for the Hecke eigenvalues of normalized eigenforms. The modern formulation of Ramanujan conjecture is given in terms of Satake parameters of the associated automorphic representation.
Is there a reference that provides clear bounds towards Ramanujan for modular forms on GL(2) over number fields in terms of Hecke eigenvalues rather than Satake parameters? The state of the art, as far as I know, is stated in the latter form and proved by Blomer and Brumley.