1972. "Sketchbook with brown-paper-covered cardboard covers, brown- cloth-covered spine and corners; and pencil sleeves. Pages of off-white, brown, buff, and gray-green wove paper. Sewn page block. Sketchbook is incomplete, with twenty-five pages remaining. Forty-seven drawings.The pages are numbered in red-brown ink in the top right hand corner. Several pages are missing and the page numbering apparently occurred after their removal. Missing are three pages after page eight; at least one page after page nine; and at least one page after page 19. The condition of this sketchbook is fragile, and many of the pages are loose."
Further reading: https://www.jstor.org/stable/4301578