Kravis, I. B., Heston, A. W., Summers, R., United Nations. Statistical Office., World Bank., & United Nations International Comparison Project. (1978). International comparisons of real product and purchasing power. Baltimore: Published for the World Bank [by] the Johns Hopkins University Press.

Kravis, Irving B., Alan W. Heston, Robert Summers, United Nations. Statistical Office, World Bank, and United Nations International Comparison Project. International Comparisons of Real Product and Purchasing Power. Baltimore: Published for the World Bank [by] the Johns Hopkins University Press, 1978.

Kravis, Irving B., et al. International Comparisons of Real Product and Purchasing Power. Baltimore: Published for the World Bank [by] the Johns Hopkins University Press, 1978.