Zhang, Lizhen; Xu, Xingzhong A necessary condition of the quadratic admissible estimate for covariance matrix. (Chinese. English summary) Zbl 1019.62054 J. Ocean Univ. Qingdao 32, No. 2, 325-328 (2002). MSC: 62H12 62C15 PDFBibTeX XMLCite \textit{L. Zhang} and \textit{X. Xu}, J. Ocean Univ. Qingdao 32, No. 2, 325--328 (2002; Zbl 1019.62054)
Zhang, Lizhen; Xu, Xingzhong The quadratic admissible estimate for covariance matrix. (Chinese. English summary) Zbl 1016.62069 J. Ocean Univ. Qingdao 31, No. 6, 950-954 (2001). MSC: 62H12 62C15 PDFBibTeX XMLCite \textit{L. Zhang} and \textit{X. Xu}, J. Ocean Univ. Qingdao 31, No. 6, 950--954 (2001; Zbl 1016.62069)