APA (7th ed.) Citation

O'Brien, D. (2006). An introduction to the theory of knowledge (1. publ.). Polity.

Chicago Style (17th ed.) Citation

O'Brien, Dan. An Introduction to the Theory of Knowledge. 1. publ. Cambridge [u.a.]: Polity, 2006.

MLA (9th ed.) Citation

O'Brien, Dan. An Introduction to the Theory of Knowledge. 1. publ. Polity, 2006.

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