1. UNODC. World Wildlife Crime Report. 2020. http://www.unodc.org/unodc/en/data-and-analysis/wildlife.html.
2. UNEP. Analysis of the environmental impacts of illegal trade in wildlife. https://wedocs.unep.org/handle/20.500.11822/17554; 2017.
3. Flying under the radar: Wildlife trafficking in the air transport sector;Utermohlen;Routes,2018
4. Avis W.. Criminal networks and illicit wildlife. K4D Tech Report, https://gsdrc.org/wp-content/uploads/2017/07/150-Illicit-Wildlife-Trade.pdf; 2017.
5. Comparing illicit trades in wildlife and drugs: An exploratory study;South;Deviant Behavior,2011