Robert O. · Robert Oberheid · Robert Obert · Robert Overton
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| A Secret History, the London Gay Men's Chorus | 978-0-9955830-1-6 (0-9955830-1-3) | 2017 |
| The Secret History: The London Gay Men's Chorus | 978-0-9955830-0-9 (0-9955830-0-5) | 2017 |