Gaya APA

TAMBUNAN, B, A. (2011). a Correlation betwen students' mastery of past tense and their achievement in writing recount . Medan: Universitas HKBP Nommensen.

Gaya MLA

TAMBUNAN, Barli, Andrian. "a Correlation betwen students' mastery of past tense and their achievement in writing recount". Medan: Universitas HKBP Nommensen, 2011. Artikel.