APA (7th ed.) Citation

(1999). Using the Gravity Model to Estimate the Costs of Protection Howard J. Wall. [electronic resource].

Chicago Style (17th ed.) Citation

Using the Gravity Model to Estimate the Costs of Protection Howard J. Wall. [electronic Resource]. 1999.

MLA (9th ed.) Citation

Using the Gravity Model to Estimate the Costs of Protection Howard J. Wall. [electronic Resource]. 1999.