1. Godambe, V. P., (1955): A unified theory of sampling from finite populations. J. Roy. Stat. Soc. Ser. B17, 269–278.
2. Horvitz, D. G. andD. J. Thompson, (1952): A generalization of sampling without replacement from a finite universe. J. Amer. Stat. Ass.47, 663–685.
3. Koop, J. C., (1957): Contributions to the general theory of sampling finite populations without replacement and with unequal probabilities. Ph.D. thesis. N. Carolina State College Library, Raleigh. [Institute of Statistics, Mimco Series No. 296 (1961).]
4. Koop, J. C., (1963): On the axioms of sample formation and their bearing on the construction of linear estimators in sampling theory for finite populations, Part I, II and III. Metrika7, 81–114 and 165–204.
5. Murthy, M. N., (1957): Ordered and unordered estimators in sampling without replacement. Sankhya18, 379–390.