Srirat, Chomphoonut, Somchit Hanucharurnkul, Suparb Aree-Ue, and Tiraporn Junda. 2015. “Similarity and Stability of Symptom Cluster in Severity and Distress among Persons with Chronic Obstructive Pulmonary Disease”. Pacific Rim International Journal of Nursing Research 19 (2):89-106. https://he02.tci-thaijo.org/index.php/PRIJNR/article/view/22473.