| Clue | Source | Date |
|---|---|---|
| Groups of four | Premier Sunday | 05 Jun 2022 |
| Groups of four, and what's spelled out by the groups of four in this puzzle's theme answers | The Washington Post Sunday | 15 Nov 2020 |
| Uplifting place hosting jazz quartets | ||
| Groups of four | Universal | 23 Dec 2018 |
| Fours, as groups | Universal | 22 Sep 2018 |
| Groups of four | ||
| Fours, as groups | ||
| Foursomes | Universal | 17 Aug 2017 |
| Foursomes | ||
| Groups of four | The Chronicle of Higher Education | 13 Nov 2015 |
| Groups of four | ||
| Foursomes | ||
| Bridge units | ||
| Groups of four | ||
| Groups of four | ||
| Bridge units | ||
| Foursomes | ||
| Double duos | ||
| Groups of four | ||
| The Beatles and others | ||
| The Beatles and others | ||
| The Horsemen et al. | ||
| The Horsemen et al. | ||
| Foursomes | ||
| Quaternities | ||
| Foursomes | ||
| Quaternities | ||
| Groups of four | ||
| Double duos | ||
| Quartets. | ||
| Foursomes |