Originally published in 1976 in UK chapbook "The Power Twins and the Worm Puzzle" as by Martin Martinsen (pseudonym for Ken Follett.)
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| September 1990 |
|
The Power Twins | William Morrow | Chapbook | |
| September 1991 |
|
The Power Twins | Apple / Scholastic | Chapbook | 1 |