求助两篇文献，非常感谢！

1[1] Trochim,William M.K. . Pattern Matching, Validity, and Conceptualization in Program Evaluation
Evaluation Review , 1985, Volume 9 (5): 575-604
[2] Campbell, Donald T. “‘Degrees of Freedom’ and the Case Study.” Ed. E Samuel Overman. Comparative Political Studies 8.2 (1975) : 178-193.

第二篇~

第一篇，搞定。

第二篇下不了。