https://www.csis.org/blogs/post-soviet-post/band-brothers-wagner-group-and-russian-state

https://carnegieendowment.org/2019/07/08/putin-s-not-so-secret-mercenaries-patronage-geopolitics-and-wagner-group-pub-79442

https://www.reuters.com/world/europe/russian-mercenary-boss-courts-putin-with-ukrainian-battlefield-success-2023-01-13/

https://www.aljazeera.com/podcasts/2022/11/18/inside-the-wagner-group-russias-mercenary-force

https://www.bbc.com/news/world-60947877