1. Barnes, R.W., Wilson, M.R.: Doppler Ultrasonic Evaluation of Peripheral Arterial Disease: A Programmed Audiovisual Instruction. Iowa City, University of Iowa, 1976, p. 296.
2. Barnes, R.W. , Wilson, M.R.: Doppler Ultrasonic Evaluation of Cerebrovascular Disease: A Programmed Audiovisual Instruction. Iowa City , University of Iowa, 1975, p. 196.
3. Barnes, R.W. , Russell, H.E., Wilson, M.R.: Doppler Ultrasonic Evaluation of Venous Disease: A Programmed Audiovisual Instruction. Second edition. Iowa City, University of Iowa, 1975 , p. 220.
4. Supraorbital photoplethysmography. Simple, accurate screening for carotid occlusive disease