1. The Japanese Ophthalmological Society (JOS) Congenital color blindness http://www.nichigan.or.jp/public/disease/hoka_senten.jsp
2. Colorimetry
3. Hira S Individual differences in chromatic perception: Continuous variation from dichromacy to trichromacy 24 992 995 2017
4. http://www.variantor.com/eaga/