@article{oai:tsukuba.repo.nii.ac.jp:00015996,
 author = {Sugiura, Nariaki},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {103--126},
 title = {Asymptotic risk comparison of improved estimators for normal convariance matrix},
 volume = {6},
 year = {1982}
}