Asif, Muhammad, et al. “ANALYSIS OF TRACHEOBRONCHIAL FOREIGN BODIES WITH RESPECT TO SEX, AGE, TYPE AND PRESENTATION”. Journal of Ayub Medical College Abbottabad, vol. 19, no. 1, Mar. 2007, pp. 13-15, https://jamc.ayubmed.edu.pk/index.php/jamc/article/view/4282.