@inbook{NBERc2550,
 Crossref = "NBERfuch72-3",
 title = "Differences Over Time, 1948-68: A Statistical Decomposition",
 author = "Victor R. Fuchs and Marcia J. Kramer",
 BookTitle = "Determinants Of Expenditures For Physicians' Services In The United States 1948-68",
 Publisher = "NBER",
 pages = "5-20",
 year = "1972",
 URL = "http://www.nber.org/chapters/c2550",
}
@book{NBERfuch72-3,
 title = "Determinants Of Expenditures For Physicians' Services In The United States 1948-68",
 author = "Victor R. Fuchs and Marcia J. Kramer",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1972",
 URL = "http://www.nber.org/books/fuch72-3",
}