APA (7th ed.) Citation

Harkness, P. (1991). The Photographic Encyclopedia of Roses. Colour Library Books.

Chicago Style (17th ed.) Citation

Harkness, Peter. The Photographic Encyclopedia of Roses. Surrey: Colour Library Books, 1991.

MLA (9th ed.) Citation

Harkness, Peter. The Photographic Encyclopedia of Roses. Colour Library Books, 1991.

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