@inbook{NBERc1636,
 Crossref = "NBERhult65-1",
 title = "Comparisons and Interpretations",
 author = "Thor Hultgren",
 BookTitle = "Cost, Prices, and Profits: Their Cyclical Relations",
 Publisher = "Columbia University Press",
 pages = "152-175",
 year = "1965",
 URL = "http://www.nber.org/chapters/c1636",
}
@book{NBERhult65-1,
 title = "Cost, Prices, and Profits: Their Cyclical Relations",
 author = "Thor Hultgren",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "Columbia University Press",
 year = "1965",
 URL = "http://www.nber.org/books/hult65-1",
}