(2012). PET 7. Cambridge: Cambridge University Press.
Trích dẫn kiểu ChicagoPET 7. Cambridge: Cambridge University Press, 2012.
MLA引文PET 7. Cambridge: Cambridge University Press, 2012.
警告：这些引文格式不一定是100％准确.
APA引文
(2012). PET 7. Cambridge: Cambridge University Press.
Trích dẫn kiểu ChicagoPET 7. Cambridge: Cambridge University Press, 2012.
MLA引文PET 7. Cambridge: Cambridge University Press, 2012.