Leopold Ziegler ยท Oswald L Ziegler
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Sydney builds an opera house | 978-0-909586-05-8 (0-909586-05-5) | 1973 |
| Sydney has an opera house | 978-0-909586-06-5 (0-909586-06-3) | 1974 |
| The world and south east Asia | 978-0-909586-03-4 (0-909586-03-9) | 1972 |