Cita APA (7a ed.)

Helpman, E. (1997). R&D and productivity: The international connection. National Bureau of Economic Research.

Cita Chicago Style (17a ed.)

Helpman, Elhanan. R&D and Productivity: The International Connection. Cambridge, MA: National Bureau of Economic Research, 1997.

Cita MLA (9a ed.)

Helpman, Elhanan. R&D and Productivity: The International Connection. National Bureau of Economic Research, 1997.