Eko, E. E. (1999). Effective writing. Heinemann Educational Books.
Chicago Style (17th ed.) CitationEko, Ebele E. Effective Writing. Heinemann Educational Books, 1999.
MLA引文Eko, Ebele E. Effective Writing. Heinemann Educational Books, 1999.
警告:這些引文格式不一定是100%准確.