Forgotten Books · Palala Press
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| On the Science of Language and Its Study: With Special Regard to South Africa | 978-1-330-21044-4 (1-330-21044-1) | 2018 |
| On the Science of Language and Its Study, with Special Regard to South Africa | 978-1-356-12692-7 (1-356-12692-8) | 2016 |