Journal of Pulmonary & Respiratory Medicine: A Review on Respiratory Muscle Training Devices
Advances in Comprehensive Pulmonary Rehabilitation for COPD Patients
https://www.researchgate.net/publication/264339632_Advances_in_Comprehensive_Pulmonary_Rehabilitation_for_COPD_Patients
European Journal of Heart Failure
Expert Reviews
Servei de Pneumologia, Hospital del Mar – IMIM, Departament de Ciències Experimentals i de la Salut (CEXS), Universitat Pompeu Fabra, CIBER de Enfermedades Respiratorias (CIBERES) ISC III,
2012
Scientific studies about Orygen Valve
By Dr. Orozco-Levi