McLaren, K. (1985). "Newton's indigo". Color Research & Application. 10 (4): 225–229. doi:10.1002/col.5080100411.
Kelly, Kenneth L. (November 1, 1943). "Color Designations for Lights". Journal of the Optical Society of America. 33 (11): 627. doi:10.1364/JOSA.33.000627.