| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Religion and Liberty: Addresses and Papers at the Second International Council of Unitarian and Other Liberal Religious Thinkers and Workers, Held in Amsterdam, September, 1903 | 978-1-112-5O749-6 (1-112-5O749-3) | 2009 |
International congress of free Christians and other religious liberals (4th)