| title | media type | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|---|
| They Called Him Mallam: The Biography of Joseph Ummel, a Pioneer Missionary to Northern Nigeria, West Africa | Paperback | 978-1-59408-284-9 (1-59408-284-7) | 2005 | Ta Zuru |
| They Called Him Mallam: The Biography of Joseph Ummel, a Pioneer Missionary to Northern Nigeria, West Africa | Hardcover | 978-1-59408-510-9 (1-59408-510-2) | 2005 | " |