Georgia O'Keeffe . Chelsea House, 1988. Bradbury, Ellen and Christopher Merrill, eds. Addison-Wesley Publishing Co, 1992. Collection of essays, half on Work and half on Life.
Work essays very good.
The Art and Life of GOK . A good, thorough introduction. Scarecrow Press, 1984. Chapter five is a good overview of sexist criticism and OK's reaction to it. Messinger, Lisa Mintz.