Christensen. (1980). Relative productivity levels, 1947- 1973: An international comparison. Cambrridge: Harvard Institute for Economic Research.
Chicago Style aipamenaChristensen. Relative Productivity Levels, 1947- 1973: An International Comparison. Cambrridge: Harvard Institute for Economic Research, 1980.
MLA aipamenaChristensen. Relative Productivity Levels, 1947- 1973: An International Comparison. Cambrridge: Harvard Institute for Economic Research, 1980.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.