Wise RA, Acevedo RA, Anzueto AR, Hanania NA, Martinez FJ, Ohar JA, Tashkin DP. Guiding Principles for the Use of Nebulized Long-Acting Beta2-Agonists in Patients with COPD: An Expert Panel Consensus. Chronic Obstr Pulm Dis. 2016 Nov 15; 4(1):7-20.