Peter Ritzmann · Petra Ritzinger
| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Opus 1 Progression in Music 11 - 14: Teacher's Resource File | 978-0-435-81211-9 (0-435-81211-4) | 2006 | Karen Brock · Chris Hiscock · Derek Hobbs · Steve Block |
| Opus Pupil Book 1 | 978-0-435-81208-9 (0-435-81208-4) | 2006 | Karen Brock · Chris Hiscock · Derek Hobbs |
| Opus Pupil Book 2 | 978-0-435-81230-0 (0-435-81230-0) | 2007 | Steve Block · Karen Brock · Chris Hiscock · Derek Hobbs |