| title | ISBN-13 (ISBN-10) | year of publica- tion |
|---|---|---|
| Dannunzio: The Poet As Superman | 978-0-8392-1022-1 (0-8392-1022-1) | 1960 |
| The Vatican in the Age of the Dictators, 1922-1945 | 978-0-03-007736-4 (0-03-007736-2) | 1974 |
| Vatican in the Age of the Dictators | 978-0-340-02394-5 (0-340-02394-5) | 1973 |