Hultgren, T. (1943). Railroad travel and the state of business. National Bureau of Economic Research.
Chicago-Zitierstil (17. Ausg.)Hultgren, Thor. Railroad Travel and the State of Business. New York: National Bureau of Economic Research, 1943.
MLA-Zitierstil (9. Ausg.)Hultgren, Thor. Railroad Travel and the State of Business. National Bureau of Economic Research, 1943.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.