@article{AM2_1977__16_136703,
     author = {Stefan Czerwik},
     title = {Solutions of a system of functional equations in some classes of functions. {(Short} {Communication).}},
     journal = {Aequationes mathematicae},
     pages = {309--309},
     publisher = {mathdoc},
     volume = {16},
     year = {1977},
     url = {http://geodesic.mathdoc.fr/item/AM2_1977__16_136703/}
}