Gaya APA

Butterworth, J., Thwaites, G. (2013). Thinking Skills : critical thinking and problem solving, Secon Edition (2nd.Ed). united kingdom: Cambridge University Press.

Gaya MLA

Butterworth, John., Thwaites, Geoff. "Thinking Skills : critical thinking and problem solving, Secon Edition". 2nd.Ed united kingdom: Cambridge University Press, 2013. Text.