Martin, E.B. 1990.Survey of wildlife products for sale in Saudi Arabia, with particular emphasis on rhino horn.Traffic Bulletin 11 (4): 66-68, map 1, tables 1-2.
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Ryan, T.C.I.; Martin, E.B. 1990.How much rhino horn has come onto international markets since 1970?.Pachyderm 13: 20-25, figs. 1-4.