1. Ahmad I. A. (1995). On multivariate kernel estimation for samples from weighted distributions, Statist. Probab. Lett., 22, 121?129.
2. Bhattacharyya B. B., Franklin L. A. and Richardson G. D. (1988). A comparison of nonparametric unweighted and length-biased density estimation of Fibres, Comm. Statist. Theory Methods, A 17, 3629?3644.
3. Cox D. R. (1969). Some sampling problems in technology, New Developments in Survey Sampling (eds. N. L. Johnson and H. SmithJr.), 506?527, Wiley-Interscience, New York.
4. Donoho D. L. and Liu R. C. (1991a). Geometrizing rates of convergence II, Ann. Statist. 19, 633?667.
5. Donoho D. L. and Liu R. C. (1991b). Geometrizing rates of convergence III, Ann. Statist., 19, 668?701.