@article{oai:tsukuba.repo.nii.ac.jp:00015745,
 author = {Watanabe, Tadashi},
 issue = {1},
 journal = {Tsukuba Journal of Mathematics},
 month = {Jun},
 pages = {17--59},
 title = {Approximative shape I -basic notions-},
 volume = {11},
 year = {1987}
}