%0 Journal Article %A S.G. Prabhu Ajgaonkar %T A Contribution to the Theory of Unique Estimators for Horvitz and Thompson's Classes of Linear Estimators %J Metrika %D 1970 %P 40-47 %V 15 %I mathdoc %U http://geodesic.mathdoc.fr/item/MET_1970__15_175413/ %F MET_1970__15_175413