| Clue | Source | Date |
|---|---|---|
| In stubbornly determined way | ||
| Barker's way, perhaps ___ obstinately! (8) | ||
| In grimly persistent way | ||
| Obstinately (8) | ||
| Wilfully (8) | ||
| With obstinate determination | ||
| Tenaciously (8) | ||
| With grim persistence | ||
| Without respite | ||
| In persistent manner | The Sun Two Speed | 29 Jul 2019 |
| Followed heartless lady with determination | The Sun Two Speed | 29 Jul 2019 |
| Followed heartless lady with determination | The Telegraph Cryptic | 27 Nov 2016 |
| "I'm determined to finish my behavioral experiments," Pavlov said ___ | ||
| With persistence | ||
| Stubbornly |