1. Gordts F, Clement PAR. Epidemiology and prevalence of aspecific chronic sinusitis. Acta Otorhinolaryngol Belg. 1997;51:205–8.
2. Maran GD, Lund VJ. Clinical rhinology. New York: Thieme; 1990.
3. Hedmann J, Kaprio J, Poussa T, Nieminen MM. Prevalence of asthma, aspirin intolerance, nasal polyposis, and chronic obstructive pulmonary disease in a population-based study. Int J Epidemiol. 1999;28:717–22.
4. Portenko GM. Prevalence of nasal polyposis rhinosinusitis among the population. Vestn Otorinolaringol. 1989;1:52–4.
5. Settipane GA. Nasal polyps, Chap. XXII. In: Settipane GA, editor. Rhinitis. The New England and regional allergy proceedings, Providence, Rhode Island; 1984. p. 133–40.