(2017). PET 6. Cambridge: Cambridge University Press.
Trích dẫn kiểu ChicagoPET 6. Cambridge: Cambridge University Press, 2017.
MLA引文PET 6. Cambridge: Cambridge University Press, 2017.
警告：這些引文格式不一定是100％准確.
APA引文
(2017). PET 6. Cambridge: Cambridge University Press.
Trích dẫn kiểu ChicagoPET 6. Cambridge: Cambridge University Press, 2017.
MLA引文PET 6. Cambridge: Cambridge University Press, 2017.