1. Wyler, L. S. & Sheikh, P. A. Congressional Research Service (2009).
2. Wasser, R. M & Jiao, P. B. Traffic East Asia Report (2010).
3. Venkataraman, B. (Comps) Traffic Southeast Asia (2007)
4. Chunyu, S. CITES Communication SC61 Doc. 41, Annex 2 (2011).
5. Environmental Investigation Agency Report (2011).