Usman Akhtar, Muhammad, et al. “VOCAL CORD PARALYSIS: WHAT MATTERS BETWEEN IDIOPATHIC AND NONIDIOPATHIC CASES? Vocal Cord Paralysis”. Pakistan Armed Forces Medical Journal, vol. 67, no. 6, Dec. 2017, pp. 943-47, https://www.pafmj.org/PAFMJ/article/view/1111.