Acoustic stethoscopes.
Wallen
Roy D
RD
Edwards Life-sciences, Irvine, CA, USA.
D006347:Heart Sounds; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D012135:Respiratory Sounds; D019023:Stethoscopes / Q000266:history; D014481:United States