Philbrick, H., & Gregg, R. B. (1991). Companion plants: Plants that help each other and how to use them (Rev. ed.). Kangaroo Press.
Chicago Style (17th ed.) CitationPhilbrick, Helen, and Richard B. Gregg. Companion Plants: Plants That Help Each Other and How to Use Them. Rev. ed. [Australia]: Kangaroo Press, 1991.
MLA (9th ed.) CitationPhilbrick, Helen, and Richard B. Gregg. Companion Plants: Plants That Help Each Other and How to Use Them. Rev. ed. Kangaroo Press, 1991.
Warning: These citations may not always be 100% accurate.