Voir la notice de l'article provenant de la source eLibrary of Mathematical Institute of the Serbian Academy of Sciences and Arts
@article{PIM_1979_N_S_26_40_a18, author = {Jovan D. Ke\v{c}ki\'c}, title = {On {Nonlinear} {Superposition,} {III}}, journal = {Publications de l'Institut Math\'ematique}, pages = {131 }, publisher = {mathdoc}, volume = {_N_S_26}, number = {40}, year = {1979}, url = {http://geodesic.mathdoc.fr/item/PIM_1979_N_S_26_40_a18/} }
Jovan D. Kečkić. On Nonlinear Superposition, III. Publications de l'Institut Mathématique, _N_S_26 (1979) no. 40, p. 131 . http://geodesic.mathdoc.fr/item/PIM_1979_N_S_26_40_a18/