Effects of formoterol, salmeterol or oxitropium bromide on airway responses to salbutamol in COPD
M Cazzola, F Di Perna, P Noschese, A Vinciguerra, F Calderaro, G Girbino, MG Matera
European Respiratory Journal 1998 11: 1337-1341; DOI: 10.1183/09031936.98.11061337