(2006). Cambridge exams extra PET with answers. Cambridge, UK: Cambidge University Press.
Trích dẫn kiểu ChicagoCambridge Exams Extra PET With Answers. Cambridge, UK: Cambidge University Press, 2006.
MLA引文Cambridge Exams Extra PET With Answers. Cambridge, UK: Cambidge University Press, 2006.
警告:这些引文格式不一定是100%准确.