Effect of simultaneous random amplitude and frequency modulation on ECG power spectra. - Vrudhula K. Murthy; John M. Richardson; L. Julian Haywood (Inf. Sci., 1977)

Recognition of generalized markoff processes and application to electrocardiography. - John M. Richardson; Vrudhula K. Murthy; L. Julian Haywood (Inf. Sci., 1978)