1. Baum, S. (2014). Higher education earnings premium: value, variation, trends. Washington, DC: The Urban Institute. http://www.urban.org/UploadedPDF/413033-Higher-Education-Earnings-Premium-Value-Variation-and-Trends.pdf . Accessed Mar 1, 2015.
2. Bowen, H. R. (1977). Investment in learning: the individual and social value of American higher education. Baltimore MD: The Johns Hopkins University Press.
3. Collins, C. S. (2011). Higher education and global poverty: university partnerships and the world bank in developing countries. Amherst, NY: Cambria Press.
4. Collins, C. S. (2012). Land-grant extension as a global endeavor: connecting knowledge and international d. The Review of Higher Education, 36(1), 91–124.
5. Collins, C. S. (2015). Land-grant extension: public good and pitfalls in evaluation. Journal of Higher Education Outreach and Engagement, 19(2), 1–28.