The Bessel-Struve intertwining operator on ℂ and mean-periodic functions. Gasmi, A., Sifi, M. (2004) International Journal of Mathematics and Mathematical Sciences
The functional equation F(ax) + F(bx+a) = F(bx) + F(ax+b), entire and almost periodic solutions. John V. Ryff (1978) Journal für die reine und angewandte Mathematik
The generalized almost periodic part of an ergodic function Gordon Woodward (1974) Studia Mathematica