@inbook{NBERc6905,
 Crossref = "NBERborj92-1",
 title = "Out-Migration and Return Migration of Puerto Ricans",
 author = "Fernando Ramos",
 BookTitle = "Immigration and the Workforce: Economic Consequences for the United States and Source Areas",
 Publisher = "University of Chicago Press",
 pages = "49-66",
 year = "1992",
 month = "January",
 URL = "http://www.nber.org/chapters/c6905",
}
@book{NBERborj92-1,
 title = "Immigration and the Workforce: Economic Consequences for the United States and Source Areas",
 author = "George J. Borjas and Richard B. Freeman",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "1992",
 URL = "http://www.nber.org/books/borj92-1",
}