Arslan, Mahmut, and Cengizhan Yavuz. “A Practical Method to Improve Preoxygenation: Using the APL Valve”. Annals of Medical Research 27, no. 1 (May 25, 2021): 0034–0037. Accessed May 18, 2024. http://www.annalsmedres.org/index.php/aomr/article/view/590.