| title | ISBN-13 | year of publica- tion | other author(s) |
|---|---|---|---|
| Blue Skies Bulgaria Student's 3rd Grade | 978-1-4058-0080-8 | 2010 | Ron Holt |
| Blue Skies Bulgaria Workbook 3rd Grade | 978-1-4058-0081-5 | 2010 | " |
| Blue Skies Cassette 2 | 978-0-582-33622-3 | 1999 | " |
| Blue Skies Cassette 3 | 978-0-582-33623-0 | 1999 | " |
| Blue Skies Student's Book 5 | 978-0-582-33619-3 | 1999 | " |
| Blue Skies: Teacher's Book Bk. 2 | 978-0-582-33602-5 | 1999 | Ronald Holt |
| Blue Skies Workbook 4: Workbook Bk. 4 | 978-0-582-33610-0 | 1999 | Ron Holt |
| Blue Skies Workbook 5: Activity Book | 978-0-582-33611-7 | 1999 | " |
| Blue Skies Workbook 6: Workbook Bk. 6 | 978-0-582-33612-4 | 1999 | " |
| Go! Grammar Practice 1: Grammar Practice Level 1 | 978-0-582-29233-8 | 1997 | |
| Go! Grammar Practice, Level 2 | 978-0-582-29234-5 | 1997 | |