1. Allen, D., & Lueck, D. (1998). The Nature of the Farm. The Journal of Law & Economics, 41, 343–386.
2. Anti-Slavery International. (2004). The Cocoa Industry in West Africa: A History of Exploitation. Retrieved May 1, 2017, from http://www.antislavery.org/includes/documents/cm_docs/2008/c/cocoa_report_2004.pdf
3. Ashagrie, K. (1993). Statistics on Child Labour. Bulletin of Labour Statistics, 3, 663–679.
4. Bauer, P. T. (1948). The Rubber Industry: A Study in Competition and Monopoly. Cambridge: Harvard University Press.
5. Beckford, G. L. (1972). Persistent Poverty: Underdevelopment in Plantation Economies of the Third World. New York: Oxford University Press.