@article{AM2_1972__8_136307,
     author = {A.N. Sarkovski},
     title = {Characterization of the {Cosine.} {(Short} {Communications).}},
     journal = {Aequationes mathematicae},
     pages = {312--312},
     publisher = {mathdoc},
     volume = {8},
     year = {1972},
     url = {http://geodesic.mathdoc.fr/item/AM2_1972__8_136307/}
}