Paul Debevec, Tim Hawkins,Chris Tchou, Haarm-Pieter Duiker,Westley Sarokin and Mark Sagar. (2000). Acquiring the reflectance field of a human face. Proc. ACM SIGGRAPH, 145–156.
Weyrich, T., Matusik, W., Pfister, H., Bickel, B., Donner, C., Tu, C., McAndless, J., Lee, J., Ngan, A., Jensen, H. W., and Gross, M. (2006). Analysis of human faces using a measurement-based skin reflectance model. Proc. ACM SIGGRAPH, 1013-1024. See the very cool presentation and demo (with matching video) of nvidia's human head, focusing primarily on skin.
