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.
French M, Neighbors D, Carswell L, Williams R, Bush L. A model for estimating industry compliance costs of food labeling regulations. Agribusiness: An International Journal. 1993;8(2):165-86.