Gaya APA

Harfield, ., Harfield, D. (2011). E-book How It Works: Book of Amazing Answers To Curious Questions, 12 . London: Imagine Publishing, Ltd..

Gaya MLA

Harfield, ., Harfield, Dave. "E-book How It Works: Book of Amazing Answers To Curious Questions, 12". London: Imagine Publishing, Ltd., 2011. Text.