[1] [1] Thouless C, Dublin H, Blanc J, et al. African Elephant Status Report 2016: An Update from the African Elephant Database (IUCN, 2016).

[2] [2] Espinoza E O, Mann M J, Lemay J P, et al. Current Research in the Pleistocene, 1990, 7: 81.

[3] [3] Espinoza E O, Mann M J, Goddard K W. Identification Guide for Ivory and Ivory Substitutes. WWF, Baltimore, 2nd ed, 1991.

[4] [4] Wasser S K, Shedlock A M, Comstock K, et al. PNAS, 2004, 101(41): 14847.

[5] [5] Wasser S K, Mailand C, Booth R, et al. PNAS, 2007, 104(10): 4228.

[6] [6] Comstock K E, Ostrander E A, Wasser S K. Conservation Biology, 2003, 17(6): 1840.

[7] [7] Wasser S K, Clark W J, Drori O, et al. Conservation Biology, 2008, 22(4): 1065.

[8] [8] Lee J C, Hsieh H M, Huang L H, et al. International Journal of Legal Medicine, 2009, 123(2): 117.

[9] [9] Suwanchatree N, Thanakiatkrai P, Linacre A, et al. International Journal of Legal Medicine, 2021, 135(1): 107.

[10] [10] Wozney K M, Wilson P J. Forensic Science International, 2012, 219(1-3): 106.

[14] [14] Edwards H G, Farwell D W, Holder J M, et al. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 1997, 53A(13): 2403.

[15] [15] Edwards H G, Jorge Villar S E, Nik Hassan N F, et al. Analytical & Bioanalytical Chemistry, 2005, 383(4): 713.

[16] [16] Shimoyama M, Ninomiya T, Ozaki Y. Analyst, 2003, 128(7): 950.

[17] [17] Shimoyama M, Morimoto S, Ozaki Y. Analyst, 2004, 129(6): 559.