Reifenrath WG, Hill JA, Robinson PB, McVey DL, Akers WA, Anjo DM, Maibach HI PMID: 7441113
Andersen KE, Maibach HI PMID: 6996901
Mathias CG, Frick OL, Caldwell TM, Yunginger JW, Maibach HI PMID: 7356355