@book{ BA03150739,
  author    = "Becker, Gary Stanley",
  title     = "Human capital : a theoretical and empirical analysis, with special reference to education",
  publisher = "National Bureau of Economic Research,Distributed by Columbia University Press",
  year      = "1964",
  series    = "National Bureau of Economic Research general series",
  number    = "no. 80",
  URL       = "https://ci.nii.ac.jp/ncid/BA03150739"
}