3) World Health Organization. Histological Typing of Lung Tumours, International Histological Classification of Tumours. World Health Organization. (1981) vol.1, p.19-21.
4) TRAVIS WD. Histological Typing of Lung and Pleural Tumours, World Health Organization International Histological Classification of Tumours. Springer. (1999) p.25-26.
5) ROVIARO GC. Is the solitary papilloma of the bronchus always a benign tumor?. ORL. (1981) vol.43, p.301-308.