Cita APA (7a ed.)

O'Brien, D. (2017). An introduction to the theory of knowledge (2nd ed., repr.). Polity.

Cita Chicago Style (17a ed.)

O'Brien, Dan. An Introduction to the Theory of Knowledge. 2nd ed., repr. Cambridge, UK ; Malden, MA: Polity, 2017.

Cita MLA (9a ed.)

O'Brien, Dan. An Introduction to the Theory of Knowledge. 2nd ed., repr. Polity, 2017.