D.K · D. Kirby · Douglas J. Kirby · Douglas K
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Exploring the sky | 978-0-273-31845-3 (0-273-31845-4) | 1972 |
| Nature in towns | 978-0-273-31843-9 (0-273-31843-8) | 1972 |
| The underwater world | 978-0-273-31844-6 (0-273-31844-6) | 1972 |