1. Alston , J.M. Craig , B.J. Pardey , P.G. 1998 Dynamics in the creation and depreciation of knowledge, and the returns to research
2. Alston , J. Chan-Kang , C. Marra , M. Pardey , P. Wyatt , T. 2000 Meta-analysis of rates of return to agricultural R&D: Ex pede herculem
3. Chapter 72 Total Factor Productivity Growth in Agriculture
4. Beintema , N.M. Stads , G.-J. 2006 Agricultural research and development in sub-Saharan Africa: An era of stagnation