@article{GDZPPN00231648X, title = {A Characterization of Sets of Constant Width.}, journal = {Mathematische Annalen}, volume = {237}, year = {1978}, pages = {15-22}, zbl = {0369.52003}, url = {http://dml.mathdoc.fr/item/GDZPPN00231648X} }
Goodey, P.R.; Woodcock, M.M. A Characterization of Sets of Constant Width.. Mathematische Annalen, Tome 237 (1978) pp. 15-22. http://gdmltest.u-ga.fr/item/GDZPPN00231648X/