Taegtmeyer, Anne B, Jörg Daniel Leuppi, and Gerd Achim Kullak-Ublick. 2012. “Roflumilast – a Phosphodiesterase-4 Inhibitor Licensed for Add-on Therapy in Severe COPD”. Swiss Medical Weekly 142 (2930):w13628. https://doi.org/10.4414/smw.2012.13628.