Binary quadratic forms and the Fourier coefficients of elliptic and Jacobi modular forms. Nils-Peter Skoruppa (1990) Journal für die reine und angewandte Mathematik
Bounding hyperbolic and spherical coefficients of Maass forms Valentin Blomer, Farrell Brumley, Alex Kontorovich, Nicolas Templier (2014) Journal de Théorie des Nombres de Bordeaux We develop a new method to bound the hyperbolic and spherical Fourier coefficients of Maass forms defined with respect to arbitrary uniform lattices.
Bounds for automorphic L-functions. H. Iwaniec, W. Duke, J. Frielander (1993) Inventiones mathematicae
Bounds for automorphic L-functions. II. H. Iwaniec, W. Duke, J.B. Firedlander (1994) Inventiones mathematicae