APA (7th ed.) Citation

Royal Horticultural Society. (1966). R.H.S. Colour Chart. Royal Horticultural Society.

Chicago Style (17th ed.) Citation

Royal Horticultural Society. R.H.S. Colour Chart. London: Royal Horticultural Society, 1966.

MLA (9th ed.) Citation

Royal Horticultural Society. R.H.S. Colour Chart. Royal Horticultural Society, 1966.

Warning: These citations may not always be 100% accurate.