On non-negative unbiased estimation of quadratic forms in finite population sampling

Vijayan, KaipillilMukhopadhyay, PBhattacharya, S2013-11-082013-11-081995-06Australian Journal of Statistics,v. 37,no. 2, p. 169–178http://hdl.handle.net/10263/5666enNon-negative quadratic unbiased estimatorBiased non-negative variance estimatorSuperpopulation modelOn non-negative unbiased estimation of quadratic forms in finite population samplingArticle