1. Koncz, J., & Flatness, A. (2007). U.S. International Services: Cross-border trade in 2006 and sales through affiliates in 2005. Survey of Current Business (October).
2. Miller, R. E., & Blair, P. D. (1985). Input-output analysis: Foundations and extensions. Englewood Cliffs: Prentice-Hall.
3. U.S. Environmental Protection Agency. (2004). Trade and environmental assessment model: Model description. Prepared for U.S. EPA, National Center for Environmental Economics, by Abt Associates, Inc., Cambridge, MA.
4. Whichard, O. G., & Borga, M. (2002). Selected issues in the measurement of U.S. International Services. Survey of Current Business (June).