@inbook{NBERc5049,
 Crossref = "NBERepst34-1",
 title = "Appendix D: Block Diagrams of Earnings Rates",
 author = "Ralph C. Epstein and Florence M. Clark",
 BookTitle = "Industrial Profits in the United States",
 Publisher = "NBER",
 pages = "653-658",
 year = "1934",
 URL = "http://www.nber.org/chapters/c5049",
}
@book{NBERepst34-1,
 title = "Industrial Profits in the United States",
 author = "Ralph C. Epstein and Florence M. Clark",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1934",
 URL = "http://www.nber.org/books/epst34-1",
}