@article{10_4064_ap_36_1_73_84,
     author = {Marek Kuczma},
     title = {Non-negative continuous solutions of a functional inequality},
     journal = {Annales Polonici Mathematici},
     pages = {73--84},
     publisher = {mathdoc},
     volume = {36},
     number = {1},
     year = {1979},
     doi = {10.4064/ap-36-1-73-84},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-36-1-73-84/}
}