[1] Pfizer Inc, Groton, CT 06340 USA
[2] Univ Massachusetts, Boston, MA 02125 USA
[3] Brown Univ, Providence, RI 02912 USA
[4] US EPA, Res Triangle Pk, NC 27711 USA
[5] Vanderbilt Univ, Med Ctr, Nashville, TN USA
[6] Johns Hopkins Univ, Baltimore, MD USA
[7] Schering Plough Corp, Res Inst, Summit, NJ USA
[8] Amer Canc Soc, Atlanta, GA 30329 USA
[9] NIOSH, Cincinnati, OH 45226 USA
[10] US Publ Hlth Serv Ret, Silver Spring, MD USA
[11] N Carolina State Univ, Raleigh, NC 27695 USA
[12] Univ Massachusetts, Lowell, MA USA