Cita APA (7a ed.)

Evenett, S. J., & Keller, W. (1998). On theories explaining the success of the gravity equation. National Bureau of Economic Research.

Cita Chicago Style (17a ed.)

Evenett, Simon J., y Wolfgang Keller. On Theories Explaining the Success of the Gravity Equation. Cambridge, MA: National Bureau of Economic Research, 1998.

Cita MLA (9a ed.)

Evenett, Simon J., y Wolfgang Keller. On Theories Explaining the Success of the Gravity Equation. National Bureau of Economic Research, 1998.