Cita APA (7th ed.)

Heap, S., & Sharratt, N. (2005). One to ten and back again. Penguin books.

Cita Chicago (17th ed.)

Heap, Sue, i Nick Sharratt. One to Ten and Back Again. London: Penguin books, 2005.

Cita MLA (8th ed.)

Heap, Sue, i Nick Sharratt. One to Ten and Back Again. Penguin books, 2005.