Etchells E, Bell C, Robb K (February 1997). "Does this patient have an abnormal systolic murmur?". JAMA277 (7): 564–71. doi:10.1001/jama.277.7.564. பப்மெட்:9032164.
Etchells E, Bell C, Robb K (February 1997). "Does this patient have an abnormal systolic murmur?". JAMA277 (7): 564–71. doi:10.1001/jama.277.7.564. பப்மெட்:9032164.