1. A Treatise on the Diseases of the Chest (facsimile edition by Classics of Medicine library);Laennec,1821
2. Studies on pulmonary acoustics. II. The transmission of tracheal sounds through freshly exenterated sheep’s lung;Hannon;Am Rev Tuberc,1929
3. Spectral characteristics of normal breath sounds;Gavriely;J Appl Physiol,1981
4. Spectral characteristics of chest wall breath sounds in normal subjects;Gavriely;Thorax,1995
5. Frequency characteristics of heart and lung sounds;Cabot;JAMA,1925