APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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