S?rheim IC, Bakke P, Gulsvik A, Pillai SG, Johannessen A, Gaarder PI, Campbell EJ, Agust? A, Calverley PM, Donner CF, Make BJ, Rennard SI, Vestbo J, Wouters EF, Par? PD, Levy RD, Coxson HO, Lomas DA, Hersh CP, Silverman EK. a1-Antitrypsin protease inhibitor MZ heterozygosity is associated with airflow obstruction in two large cohorts. Chest. 2010 Nov; 138(5):1125-32.