| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 2006 | 978-0-9554708-0-6 | Adrian Williams · Greg H. Williams · Richard W. Lewis | Police Pass National Investigators Examination Revision Crammer Textbook |
| 2007 | 978-0-9554708-3-7 | Adrian Williams · Greg Williams · Richard Lewis | National Investigators Examination (NIE) Revision Crammer Textbook 2008 |