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2. An elephant in the room: the science and well-being of elephants in captivity;JH Poole,2009
3. Harris M, Sherwin C, Harris S (2008) The welfare, housing, and husbandry of elephants in UK zoos, http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&ProjectID=13192&FromSearch=Y&Publisher=1&SearchText=wc05007&SortString=ProjectCode&SortOrder=Asc&Paging=10
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