TY - JOUR AU - Ove Frank TI - Sampling from Overlapping Subpopulation JO - Metrika PY - 1970 SP - 32 EP - 42 VL - 16 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/MET_1970__16_175447/ ID - MET_1970__16_175447 ER -