APA (7th ed.) Citation

Robertson, K. R., Burton, P., & MacKnight, B. N. (1986). A directory of Illinois systematists and ecologists.

Chicago Style (17th ed.) Citation

Robertson, Kenneth R., Philip Burton, and Bill N. MacKnight. A Directory of Illinois Systematists and Ecologists. Champaign, Ill, 1986.

MLA (9th ed.) Citation

Robertson, Kenneth R., et al. A Directory of Illinois Systematists and Ecologists. 1986.