Hursthouse, Rosalind: Ethics, Humans and other Animals. An Introduction with Readings. London/New York 2000. Internet: https://books.google.de/books?id=1I4WdoaNsckC&pg=PR1&dq=Ethics,+Humans+and+other+Animals.+An+Introduction+with+Readings.&hl=en&sa=X&ved=0ahUKEwiC7IWn3p7TAhVBnBoKHXTGBrkQ6AEIJDAA#v=onepage&q&f=false.