@article{oai:ismrepo.ism.ac.jp:00032314,
 author = {早川, 毅 and Hayakawa, Takesi},
 issue = {2},
 journal = {統計数理研究所彙報},
 month = {Dec},
 pages = {87--92},
 title = {或る種の行列の正値性とその Convexity について},
 volume = {13},
 year = {1965}
}