Fried-booth, D. L. (1993). Focus on PET ( Preliminary English Test): Tài liệu luyện thi chứng chỉ Cambridge. TP.HCM: Trẻ.
শিকাগো স্টাইলে সাইটেশনFried-booth, Diana L. Focus On PET ( Preliminary English Test): Tài Liệu Luyện Thi Chứng Chỉ Cambridge. TP.HCM: Trẻ, 1993.
এমএলএ সাইটেশনFried-booth, Diana L. Focus On PET ( Preliminary English Test): Tài Liệu Luyện Thi Chứng Chỉ Cambridge. TP.HCM: Trẻ, 1993.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.