Mancini, Marina, Faustin Z Ntoubandi, and Thilo Marauhn. "Old Concepts and New Challenges: Are Private Contractors the Mercenaries of the Twenty-first Century?." War by Contract: Human Rights, Humanitarian Law, and Private Contractors. : Oxford University Press, 2011-01-01. Oxford Scholarship Online. 2011-05-01. Date Accessed 19 Jun. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199604555.001.0001/acprof-9780199604555-chapter-17>.
Mancini, M., Ntoubandi, F., & Marauhn, T.(2011-01-01). Old Concepts and New Challenges: Are Private Contractors the Mercenaries of the Twenty-first Century?. In War by Contract: Human Rights, Humanitarian Law, and Private Contractors. : Oxford University Press. Retrieved 19 Jun. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199604555.001.0001/acprof-9780199604555-chapter-17.
Mancini, Marina, Faustin Z Ntoubandi, and Thilo Marauhn. "Old Concepts and New Challenges: Are Private Contractors the Mercenaries of the Twenty-first Century?." In War by Contract: Human Rights, Humanitarian Law, and Private Contractors. : Oxford University Press, 2011-01-01. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199604555.001.0001/acprof-9780199604555-chapter-17.
Mancini M, Ntoubandi FZ, Marauhn T. Old Concepts and New Challenges: Are Private Contractors the Mercenaries of the Twenty-first Century?. In: Francioni F, Ronzitti N. War by Contract: Human Rights, Humanitarian Law, and Private Contractors. Oxford University Press; 2011. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199604555.001.0001/acprof-9780199604555-chapter-17. Accessed June 19, 2013.