Ekpreechakul, MD, MSc, T. ., Saiphiroonthong, MD, MSc, W. ., & Chaiwong,BSc, MPH, W. . (2021). Letter to Editor: Quantitative Fit Test of Double Layer Surgical Masks . The Bangkok Medical Journal, 17(1), 70. https://doi.org/10.31524/bkkmedj.2021.15.001