| Clue | Source | Date |
|---|---|---|
| Study secondarily | New York Times | 22 May 2025 |
| Study on the side | Wall Street Journal | 27 Jun 2024 |
| Study secondarily | Wall Street Journal | 18 May 2024 |
| Study on the side | Wall Street Journal | 19 Apr 2023 |
| Study on the side | The Washington Post | 20 Nov 2020 |
| Study on the side | LA Times Daily | 20 Nov 2020 |
| Study, but not primarily | The Washington Post Sunday | 06 Oct 2019 |
| In the USA, to study as a subsidiary subject | The Times Specialist Sunday | 01 Sep 2019 |
| Study on the side |