Cochran, W. G. (1999). Sampling techniques (3rd ed.). Wiley India (P) Ltd..
Dyfyniad Arddull ChicagoCochran, William G. Sampling Techniques. 3rd ed. New Delhi: Wiley India (P) Ltd., 1999.
Dyfyniad MLACochran, William G. Sampling Techniques. 3rd ed. Wiley India (P) Ltd., 1999.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.