APA (7th ed.) Citation

King, K. L. (2003). What is gnosticism? Belknap Press of Harvard University Press.

Chicago Style (17th ed.) Citation

King, Karen L. What Is Gnosticism? Cambridge (Massachusetts) [etc.]: Belknap Press of Harvard University Press, 2003.

MLA (9th ed.) Citation

King, Karen L. What Is Gnosticism? Belknap Press of Harvard University Press, 2003.

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