@book{ BA18820052,
  author    = "Thomas, J. J.",
  title     = "Informal economic activity",
  publisher = "Harvester Wheatsheaf",
  year      = "1992",
  series    = "LSE handbooks in economics",
  number    = "",
  URL       = "https://ci.nii.ac.jp/ncid/BA18820052"
}