6Lira M, Lew-Gor S, Darby Y, et al. The relationship between subjective assessment instruments in chronic rhinosinusitis. Rhinology, 2007, 45: 144-147.
7Lurid VJ, Kennedy DW. Staging for rhinosinusitis. Otolaryngol Head Neck Surg, 1997, 117 (3 Pt2): S35-40.
8Lund VJ, Mackay IS. Staging in rhinosinusitus. Rhinology, 1993,31 : 183-184.