B. Stankiewicz, B. Adamczyk, K. Zieliński, and M. Darowski, “Visual feedback based on expired CO2 as a therapy method for respiratory disturbances in stuttering”, Arch. Acoust., vol. 31, no. 4, pp. 439–444, Apr. 2014, Accessed: Apr. 29, 2025. [Online]. Available: https://acoustics3.ippt.pan.pl/index.php/aa/article/view/733