@article{AM2_1983__26_136997,
     author = {L. Sz\'ekelyhidi},
     title = {Almost periodicity and functional equations.},
     journal = {Aequationes mathematicae},
     pages = {163--175},
     publisher = {mathdoc},
     volume = {26},
     year = {1983},
     zbl = {0566.39010},
     url = {http://geodesic.mathdoc.fr/item/AM2_1983__26_136997/}
}