Dr. Clark is still alive and runs a clinic in Mexico (ministry?). She is a Ph, D Biologist and has done years and years of research. Her own website can be found here --> http://drclark.net/
"Any positively offset [DC] frequency kills all bacteria, viruses and parasites simultaneously given sufficient voltage (5 to 10 volts), duration (seven minutes), and frequency (anything from 10 Hz to 500'000 Hz)."