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Barnes, P. Yvonne, A. C. Parr, and Edward A. Early. NIST Measurement Services: Spectral Reflectance. Gaithersburg, Md.: U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1998.

Barnes, P. Yvonne, et al. NIST Measurement Services: Spectral Reflectance. U.S. Dept. of Commerce, Technology Administration, National Institute of Standards and Technology, 1998.