Cita APA (7th ed.)

Harkness, P. (1992). Roses to enjoy. The Royal National Rose Society.

Cita Chicago (17th ed.)

Harkness, Peter. Roses to Enjoy. Albany: The Royal National Rose Society, 1992.

Cita MLA (9th ed.)

Harkness, Peter. Roses to Enjoy. The Royal National Rose Society, 1992.