“…For multi-periodic solutions of various classes of ordinary differential equations and partial differential equations, we also refer the reader to [8,9,22,27,36,37,43,52,53,55,56,58]. Especially, we would like to mention the investigations of G. Nadin [44]- [46] concerning the space-time periodic reaction-diffusion equations, G. Nadin-L.Rossi [47] concerning transition waves for Fisher-KPP equations, L. Rossi [51] concerning Liouville type results for almost periodic type linear operators, the investigation of B. Scarpellini [54] concerning the space almost periodic solutions of reaction-diffusion equations, and the recent investigation of R. Xie, Z. Xia, J. Liu [65] concerning the quasi-periodic limit functions, (ω 1 , ω 2 )-(quasi)-periodic limit functions and their applications, given only in the two-dimensional setting.…”