Williams, M. L., & Covington, B. (1999). Distance learning: The essential guide. Thousand Oaks, Calif: Sage.
シカゴスタイル引用形Williams, Marcia L., , Barbara Covington. Distance Learning: The Essential Guide. Thousand Oaks, Calif: Sage, 1999.
MLA引用形式Williams, Marcia L., , Barbara Covington. Distance Learning: The Essential Guide. Thousand Oaks, Calif: Sage, 1999.
警告: この引用は必ずしも正確ではありません.