ⓒ Copyright 1998, Korea Institute for Curriculum and Evaluation. This is an Open-Access article distributed under the terms of the Creative Commons Attribution NonCommercial-ShareAlike License (http://creativecommons.org/licenses/by-nc-sa/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Published Online: Dec 31, 1998