@book{ BN11013021,
  author    = "竹之内, 脩  and 福原, 満洲雄  and 古屋, 茂 ",
  title     = "入門集合と位相",
  publisher = "実教出版",
  year      = "1991",
  URL       = "https://ci.nii.ac.jp/ncid/BN11013021"
}