Beach RH, Poulos C, Pattanayak SK. Farm economics of bird flu. Revue Canadienne D'agroeconomie. 2007 Dec 1;55(4):471-83.
Urrutia I, Aguirre U, Sunyer J, Plana E, Muniozguren N, Martinez-Moratalla J. Changes in the prevalence of asthma in the Spanish cohort of the European Community Respiratory Health Survey (ECRHS-II). Arch. Bronconeumol. 2007 Aug;43(8):425-30.