Ambiguous Loci of the Metric Projection Onto Compact Starshaped Sets in a Banach Space. P.S. Kenderov; F.S. De Blasi — 1995 Monatshefte für Mathematik
Properties of typical bounded closed convex sets in Hilbert space. de Blasi, F.S.; Zhivkov, N.V. — 2005 Abstract and Applied Analysis