Jiménez-Ruiz, C.A., and K.O. Fagerström. “Smoking Cessation Treatment for COPD Smokers: The Role of Counselling”. Monaldi Archives for Chest Disease 79, no. 1 (November 26, 2015). Accessed June 21, 2021. https://monaldi-archives.org/index.php/macd/article/view/107.