中国科学院数学与系统科学研究院期刊网
THE BEST NONNEGATIVE ESTIMATOR OF COVARIANCE MATRIX IN GROWTH CURVE MODEL
Yang Wen-li, Jiang Wen-jiang
Acta Mathematicae Applicatae Sinica . 1992, (1): 83 -98 .  DOI: 10.12387/C1992009