APA (7th ed.) Citation

McGowan, D. J. (1992). What is an ecosystem? Encyclopedia Britannica Educational Corporation.

Chicago Style (17th ed.) Citation

McGowan, David J. What Is an Ecosystem? Chicago: Encyclopedia Britannica Educational Corporation, 1992.

MLA (9th ed.) Citation

McGowan, David J. What Is an Ecosystem? Encyclopedia Britannica Educational Corporation, 1992.

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