| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 1991 | 978-0-9632156-0-4 | Charles A. Kenworthy | Treasure Signs, Symbols, Shadow and Sun Signs |
| 1993 | 978-0-9632156-1-1 | '' | Spanish Monuments and Trailmarkers to Treasure in the United States |
| 1994 | 978-0-9632156-2-8 | '' | Death Traps to Treasure: Spanish and Mexican Mine Traps, Warning Signs and Symbols |
| 1997 | 978-0-9632156-3-5 | '' | Treasure Secrets of the Lost Dutchman |
| 1995 | 978-0-9632156-4-2 | '' | Unfound Treasures of Mexico |