Peterson, P. W. (2005). Changing times changing tenses: A review of the English tenses system. Washington, DC.: United states Department of state.
Trích dẫn kiểu ChicagoPeterson, Patricia Wilcox. Changing Times Changing Tenses: A Review of the English Tenses System. Washington, DC.: United states Department of state, 2005.
Trích dẫn MLAPeterson, Patricia Wilcox. Changing Times Changing Tenses: A Review of the English Tenses System. Washington, DC.: United states Department of state, 2005.
Cảnh báo: Các trích dẫn này có thể không phải lúc nào cũng chính xác 100%.