1. Interpol. "Wildlife." Interpol, Lyon, France, 2008.
2. World Wildlife Crime Report: Trafficking in Protected Species;UNODC,2016
3. Distinguishing extant elephants ivory from mammoth ivory using a short sequence of cytochrome b gene;Ngatia;Sci. Rep.,2019
4. Four Years After the CITES Ban: Illegal Killing of Elephants, Ivory Trade and Stockpiles;Dublin,1995
5. AB 96 Animal Parts and Products: Importation or Sale of Ivory and Rhinoceros horn, CA 2015.