Proceedings of the twelfth annual international conference of the IEEE enginering in medicine and biology society (12; 1990; Philadelphia) : BIOELECTRIC AND BIOPHYSICAL ASPECTS OF BIOENGINEERING, MOLECULAR ELECTRONICS, MODELS OF PHYSIOLOGICAL SYSTEMS. 4/5. - IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCEITY (Piscataway : The Institute of Electrical and Electronics Engineers, Inc., 1990)