Bertie, a young hippopotamus, has trouble going to bed at night.
- ISBN13 9780735823136
- Publish Date 1 November 2010 (first published 1 May 2008)
- Publish Status Out of Stock
- Out of Print 10 January 2017
- Publish Country US
- Imprint North-South Books
- Format Paperback
- Pages 32
- Language English