Langan John. (2005). User's Guide: College Writing Skills and College Writing Skills with Readings (Tái bản lần thứ 6.). American: MC Graw Hill.
Παραπομπή Chicago StyleLangan John. User's Guide: College Writing Skills and College Writing Skills With Readings. Tái bản lần thứ 6. American: MC Graw Hill, 2005.
Παραπομπή MLALangan John. User's Guide: College Writing Skills and College Writing Skills With Readings. Tái bản lần thứ 6. American: MC Graw Hill, 2005.
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