| Clue | Source | Date |
|---|---|---|
| Light sources in pre-electricity days | USA Today | 28 Nov 2018 |
| Frontier lights | New York Times | 02 Sep 2018 |
| Pal's limo breaks old lights | ||
| Frontier lights | ||
| Light sources in pre-electricity days | ||
| Light sources | ||
| Antique sources of light | ||
| Old-time illuminants |