Lötvall J, Bateman ED, Bleecker ER, Busse WW, Woodcock A, Follows R, Lim J, Stone S, Jacques L, Haumann B. 24-h duration of the novel LABA vilanterol trifenatate in asthma patients treated with inhaled corticosteroids. Eur Respir J. 2012 Sep; 40(3):570-9.