3David H. Hamburger. The Project Manager: Risk Taker and Contigency Planner[J]. Project Manager Journal, 1990,21 (4).
4Robert N. Charette.Software Engineering Risk Analysis and Management[M].New York:Mcgraw-Hill Book Company, 1989.
5V. K. Smith. A Comparison of Direct and Indirect Methods for Estimating Enviromental Benefits[J]. American Journal of Agricultural Economics,1986, (5) :280 - 290.
