[1] West Los Angeles Vet Affairs Med Ctr, 11301 Wilshire Blvd, Los Angeles, CA 90073 USA
[2] RAND Corp, Southern Calif Evidence Based Practice Ctr, 1776 Main St, Santa Monica, CA 90401 USA
[3] UCLA, Louise M Darling Biomed Lib, 12-077 Ctr Hlth Sci, Los Angeles, CA 90095 USA
[4] Humana Inc, 500 W Main St,HUM 14, Louisville, KY 40202 USA