| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| The Leader's Voice | 978-1-59079-152-3 (1-59079-152-5) | 2008 | Crossland Ron · Clark Boyd · Boyd Clark |
| The Leader's Voice: How Your Communication Can Inspire Action and Get Results! | 978-1-59079-016-8 (1-59079-016-2) | 2002 | Boyd Clark |