1. Committee on Electrocardiography. Recommendations for standardization of leads and of specifications for instruments in electrocardiography and vectorcardiography;American Heart Association 1967;Circulation
2. 1950. The development of the electrocardiograph in Great Britain;Barron, S.L.;British Medical Journal
3. Whither electrocardiography?;Butterworth, J.S.; Glassman, E.;American Heart Journal,1973
4. Portable electrocardiograph giving direct ink tracings;Duchosal, P.; Luthi, R.;American Heart Journal,1932