| title | ISBN-13 | year of publica- tion | other author(s) |
|---|---|---|---|
| International Primary English as a Second Language Student's Book Stage 5 | 978-0-00-821370-1 | 2017 | Kathryn Gibbs · Robert Kellas |
| International Primary English as a Second Language Teacher Guide Stage 5 | 978-0-00-821372-5 | 2017 | Kathryn Gibbs · Robert Kellas |
| International Primary English as a Second Language Workbook Stage 5 | 978-0-00-821371-8 | 2017 | Kathryn Gibbs · Robert Kellas |
| International Primary English as a Second Language Workbook Stage 6 | 978-0-00-821374-9 | 2017 | Kathryn Gibbs · Robert Kellas |