Yap, N. T. (1999). Strategies for writing business letters among selected weak ESL learners at Universiti Putra Malaysia / Yap Ngee Thai.
芝加哥风格引文Yap, Ngee Thai. Strategies for Writing Business Letters Among Selected Weak ESL Learners at Universiti Putra Malaysia / Yap Ngee Thai. 1999.
MLA引文Yap, Ngee Thai. Strategies for Writing Business Letters Among Selected Weak ESL Learners at Universiti Putra Malaysia / Yap Ngee Thai. 1999.
警告：这些引文格式不一定是100％准确.