@article{10_4064_ap_24_2_209_217,
     author = {S. Czerwik},
     title = {On the differentiability of solutions of a functional equation with respect to a parameter},
     journal = {Annales Polonici Mathematici},
     pages = {209--217},
     publisher = {mathdoc},
     volume = {24},
     number = {2},
     year = {1970},
     doi = {10.4064/ap-24-2-209-217},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-24-2-209-217/}
}