Beers, Diane L.: For the prevention of cruelty: the history and legacy of animal rights activism in the United States. Athens, Ohio 2006. Internet: https://books.google.de/books?id=q2sHhHggZMoC&printsec=frontcover&dq=For+the+Prevention+of+Cruelty.+The+History+and+Legacy+of+Animal+Rights+Activism+in+the+United+States.&hl=en&sa=X&redir_esc=y#v=onepage&q&f=false. Zuletzt geprüft am: 4.5.2017.