APA (7th ed.) Citation

Sheldon, D., & Heap, S. (1991). Harry the explorer. Walker Books.

Chicago Style (17th ed.) Citation

Sheldon, Dyan, and Sue Heap. Harry the Explorer. London: Walker Books, 1991.

MLA (9th ed.) Citation

Sheldon, Dyan, and Sue Heap. Harry the Explorer. Walker Books, 1991.

Warning: These citations may not always be 100% accurate.