Rothfels 2002, pp. 6–8 Rothfels, Nigel (2002), Savages and Beasts: The Birth of the Modern Zoo, Johns Hopkins University Press, ISBN0-8018-6910-2excerpt
Rothfels 2002, pp. 143–45 Rothfels, Nigel (2002), Savages and Beasts: The Birth of the Modern Zoo, Johns Hopkins University Press, ISBN0-8018-6910-2excerpt
Rothfels 2002, pp. 160–61 Rothfels, Nigel (2002), Savages and Beasts: The Birth of the Modern Zoo, Johns Hopkins University Press, ISBN0-8018-6910-2excerpt
Rothfels 2002, pp. 162–63 Rothfels, Nigel (2002), Savages and Beasts: The Birth of the Modern Zoo, Johns Hopkins University Press, ISBN0-8018-6910-2excerpt
Qtd. in Rothfels 2002, pp. 163 Rothfels, Nigel (2002), Savages and Beasts: The Birth of the Modern Zoo, Johns Hopkins University Press, ISBN0-8018-6910-2excerpt
