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Authors: Ratcliffe, Sarah J.; Guo, Wensheng; Ten Have, Thomas R.
Document Type: Research Article
Affiliations: Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Blockley Hall, 6th Floor, 423 Guardian Drive, Philadelphia, Pennsylvania 19104-6021, U.S.A.
Publication date: December 1, 2004