@article{Rao1978,
        title = {Optimal estimation of a finite population mean under generalized
	random permutation models},
        author = {J. N. K. Rao and D. R. Bellhouse},
        journal = {Journal of Statistical Planning and Inference},
        number = 2,
        pages = {125--141},
        volume = 2,
        year = 1978,
        url = {http://www.sciencedirect.com/science/article/B6V0M-45FCS9J-3X/1/818900c18064a7c17e335ef2268859f2},
        biburl = {http://www.bibsonomy.org/bibtex/2eaec36cae13855eec55e91f59aaced94/smicha},
	keywords = {"Optimal" Estimation}
}