Davoudi M, Colt HG, Osann KE, Lamb CR, Mullon JJ. Endobronchial ultrasound skills and tasks assessment tool: assessing the validity evidence for a test of endobronchial ultrasound-guided transbronchial needle aspiration operator skill. Am J Respir Crit Care Med. 2012 Oct 15; 186(8):773-9.