APA (7th ed.) Citation

Clausen, R. R., & Ekstrom, N. H. (1989). Perennials for American gardens. Random House.

Chicago Style (17th ed.) Citation

Clausen, Ruth Rogers, and Nicolas H. Ekstrom. Perennials for American Gardens. New York: Random House, 1989.

MLA (9th ed.) Citation

Clausen, Ruth Rogers, and Nicolas H. Ekstrom. Perennials for American Gardens. Random House, 1989.