APA-Zitierstil (7. Ausg.)

Gray, E., & O'Sullivan, N. Practice Tests for the PET 1 Preliminary English Test: Class CDs. Express Publishing.

Chicago-Zitierstil (17. Ausg.)

Gray, Elisabeth, und Neil O'Sullivan. Practice Tests for the PET 1 Preliminary English Test: Class CDs. Newbury: Express Publishing.

MLA-Zitierstil (8. Ausg.)

Gray, Elisabeth, und Neil O'Sullivan. Practice Tests for the PET 1 Preliminary English Test: Class CDs. Express Publishing.