Source: U.S. Bureau Of Mines, Mineral Resources 1929, Part Ii, P.582.
This NBER data series a01207 appears on the NBER website in Chapter 1 at http://www.nber.org/databases/macrohistory/contents/chapter01.html.
NBER Indicator: a01207
Release: NBER Macrohistory Database
National Bureau of Economic Research, Coke Production, Beehive and Byproduct for United States [A01207USA448NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A01207USA448NNBR/, October 10, 2015.