1. Allen , N. L. Holland , P. W. Thayer , D. T. Approaches to nonignorable nonresponse with application to selection bias. (Research Report) Princeton, NJ Educational Testing Service
2. Allen , N. L. Holland , P. W. Thayer , D. T. A missing data approach to estimating distributions of scores for optional test sections. (Research Report) Princeton, NJ Educational Testing Serivce