[1] Harvard Univ, Massachusetts Hall, Cambridge, MA 02138 USA
[2] Harvard Med Sch, Countway Lib, 10 Shattuck St, Boston, MA 02115 USA
[3] Boston Hlth Care Homeless Program, 780 Albany St, Boston, MA 02118 USA
[4] Boston Univ, Sch Med, Boston Med Ctr, 72 E Concord St, Boston, MA 02118 USA
[5] San Francisco Dept Publ Hlth, 25 Ness Ave,Suite 500, San Francisco, CA 94102 USA