@inbook{NBERc12895,
 Crossref = "NBERbous12-1",
 title = "Comment on "Two Twentieth Century Fertility Transitions: Implications for Human Capital"",
 author = "Richard Easterlin",
 BookTitle = "Human Capital and History: The American Record",
 Publisher = "University of Chicago Press",
 year = "2012",
 month = "December",
 URL = "http://www.nber.org/chapters/c12895",
}
@book{NBERbous12-1,
 title = "Human Capital and History: The American Record",
 author = "Leah Platt Boustan and Carola Frydman and Robert A. Margo",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "2013",
 URL = "http://www.nber.org/books/bous12-1",
}