1. Cross-Level Inference;Achen,1995
2. An alternative to ecological correlation;Duncan;American Sociological Review,1953
3. Ecological regressions and voting rights;Freedman;Evaluation Review,1991
4. A rule for inferring individual-level relationships from aggregate data;Firebaugh;American Sociological Review,1978
5. Data Analysis Using Regression and Multilevel/Hierarchical Models;Gelman,2007