Kendal, Rinjong, Pantitra Sudadet, Jindarphorn Suttayamuk, and Panchanita Tuenkplee. “Evaluating a Modified Sputum Preparation Method for Improved qRT-PCR Detection of COVID-19”. Research Medical Journal 48, no. 3 (July 25, 2025): e270736. accessed September 19, 2026. https://he02.tci-thaijo.org/index.php/ramajournal/article/view/270736.