Real FG, Svanes C, Omenaas ER, Anto JM, Plana E, Janson C. Menstrual irregularity and asthma and lung function. J Allergy Clin Immunol. 2007 Sep;120(3):557-64.
Cheraghi-Sohi S, Bower P, Mead N, McDonald R, Whalley D, Roland M. Making sense of patient priorities: applying discrete choice methods in primary care using 'think aloud' technique. Fam Pract. 2007 Jun 1;24(3):276-82.