00268nam a2200133Ia 4500020001800000082001100018100001900029245002400048250000600072260003300078300000800111500000900119650000600128  a0 85226 122 5  a519.93  aCochran, W. G. 0aSampling Techniques  a-  aN. DelhibWiley Eastern Ltd.  a413  a1495  a-