Wetter, J. J. (2011). The impacts of research and development expenditures: The relationship between total factor productivity and U.S. gross domestic product performance. Springer.

Wetter, John J. The Impacts of Research and Development Expenditures: The Relationship Between Total Factor Productivity and U.S. Gross Domestic Product Performance. New York, NY: Springer, 2011.

Wetter, John J. The Impacts of Research and Development Expenditures: The Relationship Between Total Factor Productivity and U.S. Gross Domestic Product Performance. Springer, 2011.