http://uriahkriegel.com/downloads/BreakfastWithNoHog.pdf



http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1111&context=bts




http://books.google.it/books?id=aGIpwjtWnJcC&printsec=front_cover&redir_esc=y




http://books.google.it/books?id=DTY4rYdJ504C&printsec=front_cover&redir_esc=y




http://books.google.it/books?id=qIedlXtHTO8C&printsec=front_cover&redir_esc=y