00387nam a2200121Ia 4500082002100000100001700021245008100038260003600119300001600155500008400171500000500255700000500260  a515.73bSi617.BA  aSinger, Ivan  aBest approximation in normed linear spaces by elements of linear subspacesb  aNew YorkbSpringer-Verlagc1970  a415p. Index  a(Die Grundlehran der mathematischen Wissenschaften in Einzeldarstellungen, 171)  a  a