1. Al- Jararha J (2013) A class of sampling two units with probability proportional to size. Comm Stat Simul Comp 42:1906–1916
2. Basu D (1977) An essay on the logical foundation of survey sampling, part one. In: Godambe VP, Sprott DA (eds) Foundations of statistical inference. Holt, Rinehart and Winston, Toronto
3. Brewer KRW (1963) A model of systematic sampling with unequal probabilities. Aust J Stat 5:5–13
4. Brewer KRW, Hanif M (1983) Sampling with unequal probabilities, In: Lecture notes in statistics, vol 15, Springer
5. Cochran WG (1977) Sampling Techniques, 3rd edn. Wiley, N.Y