1. Botts, R.R., and J.N. Boles. 1958. Use of normal-curve theory in crop insurance ratemaking. Journal of Farm Economics 40(3): 733–740.
2. Charpentier, A. 2008. Insurability of climate risks. Geneva Papers on Risk and Insurance—Issues and Practice 33(1): 91–109.
3. Coble, K.H., T.O. Knight, B.K. Goodwin, M.F. Miller, and R.M. Rejesus. 2010. A comprehensive review of the RMA APH and COMBO rating methodology: Final report. USDA–Risk Management Agency. http://www.researchgate.net/profile/Keith_Coble/publication/228651550_A_Comprehensive_Review_of_the_RMA_APH_and_COMBO_Rating_Methodology_Final_Report/links/09e415104309966cc5000000.pdf . Accessed 2 June 2015.
4. Exell, R.H.B. 2001. Error analysis. Thonburi: King Mongkut’s University of Technology. http://www.jgsee.kmutt.ac.th/exell/PracMath/ErrorAn.htm . Accessed 2 June 2015.
5. Fan, H. 1997. Theory of errors and least squares adjustment. Geodesy Report No. 2015. Stockholm: Tekniska Högskolan. http://gidec.abe.kth.se/kurser/Theory%20of%20errors.pdf . Accessed 2 June 2015.