Eun-Kyoung Han, Yujin Suh. “Factors Influencing Quality of Sleep of Elderly Persons Based on Theory of Unpleasant Symptoms: The 2018 Nationwide Community Health Survey in Korea”. Annals of the Romanian Society for Cell Biology, Jan. 2021, pp. 1770-81, http://annalsofrscb.ro/index.php/journal/article/view/293.