8[3]MacKinnon D P, Lockwood C M, Hoffman J M, West S G, Sheets V. A Comparison of methods to test mediation and other intervening variable effects. Psychological Methods, 2002, 7(1): 83～104
9[4]MacKinnon D P, Lockwood C M, Hoffman J M. A new method to test for mediation. Paper presented at the annual meeting of the Society for Prevention Research, Park City, UT. 1998, June
10[5]Duncan O D, Featherman D L, Duncan B. Socioeconomic background and achievement. New York: Seminar Press, 1972
