@article{10_4064_ap_19_3_271_286,
     author = {H. \'Swiatak},
     title = {On some symmetrical equations of the form $f_1(x_1+...+x_n) = \ensuremath{\sum}_{i_1,...,i_n}) f_1(x_i_1)...f_n(x_i_n)$},
     journal = {Annales Polonici Mathematici},
     pages = {271--286},
     publisher = {mathdoc},
     volume = {19},
     number = {3},
     year = {1967},
     doi = {10.4064/ap-19-3-271-286},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-19-3-271-286/}
}