Chatchawan Panraksa. (2016) Knowledge space theory and union-closed sets conjecture. <i>Songklanakarin Journal of Science and Technology (SJST)</i>, <i>38</i>(4), 449-451.Chatchawan Panraksa. "Knowledge space theory and union-closed sets conjecture". Songklanakarin Journal of Science and Technology (SJST) 38 (2016):449-451.Chatchawan Panraksa. Knowledge space theory and union-closed sets conjecture. Research and Development Office, Prince of Songkla University:ม.ป.ท. 2016.