APA-viite (7. p.)

Babbage, K. J. (2010). The extreme principle: What matters most, what works best. Rowman & Littlefield Education.

Chicago-viite (17. p.)

Babbage, Keen J. The Extreme Principle: What Matters Most, What Works Best. Lanham: Rowman & Littlefield Education, 2010.

MLA-viite (9. p.)

Babbage, Keen J. The Extreme Principle: What Matters Most, What Works Best. Rowman & Littlefield Education, 2010.