Some Improved Estimators In Systematic Sampling Under Non-response
  In this paper we have considered the problem of estimating the population mean in systematic sampling using information on an auxiliary variable in presence of non response. Some modified ratio, product and difference type estimators in systematic sampling have been suggested and their properties are studied. The expressions of mean squared errors (MSEs) up to the first order of approximation are derived. An empirical study is carried out to judge the best estimator out of the suggested estimators. 
Hemant K. Verma, R. D. Singh and Rajesh Singh
stat.ME math.ST stat.TH