O'Connell, S. (1989). Focus on proficiency. Collings: London and Galasgow.
Trích dẫn kiểu ChicagoO'Connell, Sue. Focus On Proficiency. Collings: London and Galasgow, 1989.
MLA引文O'Connell, Sue. Focus On Proficiency. Collings: London and Galasgow, 1989.
警告：这些引文格式不一定是100％准确.