1. Newton, I.: Opticks. In: MacAdam, D. (ed.) Sources of Color Science. The MIT Press, Cambridge, MA (1970 [1704])
2. Kuehni, R., Schwarz, A.: Color ordered. Oxford University Press, New York (2008)
3. Russell, B.: History of Western Philosophy. George Allen & Unwin, London (1961)
4. Gage, J.: Colour and Culture. Thames and Hudson, London (1993)
5. Hård, A.: Quality Attributes of Colour Perception. Fackskrift Nr 8. The Swedish Color Centre Foundation, Stockholm (1969)