1. Continuity of set valued metric projections;Blatter;Math. Annalen.,1968
2. Best n-dimensional approximation of functions;Brown,1964
3. Applications of duality in approximation theory;Buck,1965
4. Minimum-stable wedges of semi-continuous functions;Edwards;Math. Scand.,1966
5. Holmes, R. B., On the Continuity of Best-Approximation Operators contributed to Symposium on Infinite Dimensional Topology.