1. Bahl S, Tuteja RK (1991) Ratio and product type exponential estimator. Inf Optim Sci 12:159–163
2. Chand L (1975) Some ratio type estimator based on two or more auxiliary variables. Unpublished Ph.D. dissertation, Lowa State University, Ames, Lowa
3. Cochran WG (1977) Sampling techniques. Wiley, New-York
4. Dash PR, Mishra G (2011) An improved class of estimators in two-phase sampling using two auxiliary variables. Commun Stat Theory Methods 40:4347–4352
5. Khare BB, Rehman HU (2013) Improved chain type estimators for population mean using two auxiliary variables and double sampling scheme. Int J Appl Stat Probab 1(3):82–87