Gray, E., & O'Sullivan, N. Practice Tests for the PET 1 Preliminary English Test: Class CDs. Express Publishing.
Chicagoスタイル(17版)引用形式Gray, Elisabeth, , Neil O'Sullivan. Practice Tests for the PET 1 Preliminary English Test: Class CDs. Newbury: Express Publishing.
MLA(8版)引用形式Gray, Elisabeth, , Neil O'Sullivan. Practice Tests for the PET 1 Preliminary English Test: Class CDs. Express Publishing.
警告: この引用は必ずしも正確ではありません.