Context of Basic functions of cations in myocardial activity : proceedings of the sixth annual meeting of the International Study Group for Research in Cardiac Metabolism, 25-28 September 1973, Freiburg, Germany, jointly held by the European and American research groups ; sponsored by Gesellschaft für Strahlen- und Umweltforschung mbH., Munich ; edited by Albrecht Fleckenstein and Naranjan S. Dhalla