Cita APA (7a ed.)

Keller, W. (2001). The geography and channels of diffusion at the world's technology frontier. National Bureau of Economic Research.

Cita Chicago Style (17a ed.)

Keller, Wolfgang. The Geography and Channels of Diffusion at the World's Technology Frontier. Cambridge, MA: National Bureau of Economic Research, 2001.

Cita MLA (9a ed.)

Keller, Wolfgang. The Geography and Channels of Diffusion at the World's Technology Frontier. National Bureau of Economic Research, 2001.