
https://africanarguments.org/2023/07/paul-biyas-ghostly-legacy-in-cameroon-the-absence-that-shaped-a-nation/

https://www.nao.org.uk/wp-content/uploads/2017/07/The-Customs-Declaration-Service.pdf

https://fpc.org.uk/wp-content/uploads/2020/12/Partnerships-for-the-future-of-UK-Foreign-Policy-December-FPC-publication.pdf