1. Basic Colour Terms;Berlin,1969
2. Development of 1929 Munsell book of atlas: A historical Review;Berns;Col. Res. Appl.,1985
3. Principle of Colour Technology;Billmeyer,1981
4. Microform Services, Inc;Billmeyer,1985
5. Survey of colour order systems;Billmeyer;Col. Res. Appl.,1987