The problem part of the essay is by Jan Struther and the solution part is by L. A. Graham.
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| 1962 |
|
The Mathematical Magpie | Simon & Schuster | Anthology | 298 |
| May 1997 |
|
The Mathematical Magpie | Copernicus | Anthology |