@inbook{NBERc3280,
 Crossref = "NBERhans70-1",
 title = "Skills, Human Capital, and Comparative Advantage",
 author = "Peter B. Kenen",
 BookTitle = "Education, Income, and Human Capital",
 Publisher = "NBER",
 pages = "193-240",
 year = "1970",
 URL = "http://www.nber.org/chapters/c3280",
}
@book{NBERhans70-1,
 title = "Education, Income, and Human Capital",
 author = "W. Lee Hansen",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1970",
 URL = "http://www.nber.org/books/hans70-1",
}