@article{AM2_1971__7_136258,
     author = {J. ACZ\'EL},
     title = {On a {Functional} {Equation} of the {Theory} of {Curves} in {Two} {Dimensional} {Conformal} {Geometry}},
     journal = {Aequationes mathematicae},
     pages = {246--248},
     publisher = {mathdoc},
     volume = {7},
     year = {1971},
     zbl = {0237.39009},
     url = {http://geodesic.mathdoc.fr/item/AM2_1971__7_136258/}
}