By John Berth-Jones, Eunice Tan, Howard I. Maibach, Dee McLean, London, UK
By Eric D. Winegar (Air Toxics Limited, Rancho Cordova, California, USA), Howard I. Maibach, Lawrence H. Keith, Otto G. Raabe, Ronald C. Wester (University of California, San Francisco
By Sarah H. Wakelin, Howard I. Maibach, Clive B. Archer