Wikstrand J, Berglund G, Wilhelmsen L, Wallentin I
Aust N Z J Med. 1976;6 suppl 2:1-7. doi: 10.1111/j.1445-5994.1976.tb03316.x.
The prevalence of signs of heart involvement was studied non-invasively with orthogonal and conventional ECG, apexcardiogram, carotid pulse tracing and phonocardiogram in a group of untreated hypertensives (n = 35) and a reference group (n = 73). All were derived by screening a random population sample of 50-year-old men.