1. Ahlmann, M. A., & Garrett, J. (2015). Human intelligence: the discipline the intelligence community must struggle to rediscover. American Military University.
2. Aid, M. M. (2003). All glory is fleeting: Sigint and the fight against international terrorism. Intelligence and National Security, 18(4), 72-120.
3. Badiru, A. B., & Maloney, A. E. (2016). A conceptual framework for the application of systems approach to intelligence operations: Using HUMINT to augment SIGINT. American Intelligence Journal, 33(2), 41-46.
4. Ball, D., & Tanter, R. (2015). US signal intelligence (SIGINT) activities in Japan 1945-2015: A Visual Guide. Nautilus Institute NAPS Net Special Report, December, 22.
5. Bwana, R. (2023). Inside the National Intelligence Service: A Closer Look at Kenya’s Security Apparatus. Available at SSRN 4454565.