1Gakidou E, Cowling K, Lozano R,et al. Increased educa- tional attainment and its effect on child mortality in 175 countries between 1970 and 2009: a systematic analysis[J].Lancet. 2010,376(9745):959-74.
2Brydges R, Carnahan H, Rose D, et al. Coordinating progressive levels of simulation fidelity to maximize edu- cational benefit. 2010,85(5) :806-12.
