Scheicher, M. E., Terra Filho, J. and Vianna, E. O. (2003) “Sputum induction: review of literature and proposal for a protocol”, São Paulo Medical Journal, 121(5), pp. 213–219. Available at: https://periodicosapm.emnuvens.com.br/spmj/article/view/2641 (Accessed: 15 March 2025).