1. A Color Notation, 2nd ed., Geo. H. Ellis Co., Boston, 1907. (I refer to the second edition of his book, not only because it is revised and enlarged, including his “second thoughts.” but because, thanks to my friend Samuel Kitrosser I have a copy.)
2. Preliminary Report of the OSA Subcommittee on the Spacing of the Munsell Colors
3. Final Report of the OSA Subcommittee on the Spacing of the Munsell Colors*
4. A Color Notation, 12th edition, Munsell Color Company, Baltimore, 1946. (Munsell died in 1918. This edition of Ref. 1 was edited by his son A. E. O. Munsell, who wrote in the preface. “Mr. Munsell had in mind a revision of ‘A Color Notation.’ A careful study of his published works and unpublished notes has enabled the editors to present the three dimensions of color in a manner consistent with his later ideas.”)