@article{MAN_1973__205_162491,
     author = {Dimitri Koutroufiotis},
     title = {On a {Conjectured} {Characterization} of the {Sphere.}},
     journal = {Mathematische Annalen},
     pages = {211--218},
     publisher = {mathdoc},
     volume = {205},
     year = {1973},
     zbl = {0257.53056},
     url = {http://geodesic.mathdoc.fr/item/MAN_1973__205_162491/}
}