@article{oai:ynu.repo.nii.ac.jp:00009084,
 author = {Yamada, Yoichi},
 issue = {2},
 journal = {Yokohama Mathematical Journal = 横濱市立大學紀要. D部門, 数学},
 month = {},
 pages = {1--6},
 title = {OBSERVING A SOLID ANGLE FROM VARIOUS VIEWPOINTS},
 volume = {54},
 year = {2008}
}