Robert Gorrell · Robert Gourlay · Robert Grillo
| title | ISBN-13 (ISBN-10) | year of publica- tion |
|---|---|---|
| The Art of Bowing Practice: The Expressive Bow Technique | 978-0-85249-791-3 (0-85249-791-1) | 1991 |
| The Art of Practising the Violin: With Useful Hints for All String Players | 978-0-85249-506-3 (0-85249-506-4) | 1983 |