Multidisciplinary perspectives in event-related brain potential research : proceedings of the Fourth International Congress on Event-Related Slow Potentials of the Brain (EPIC IV), Hendersonville, North Carolina, April 4-10, 1976 / edited by David A. Otto, Health Effects Research Laboratory, Office of Research and Development, Research Triangle Park, N.C., and Biological Sciences Research Center, University of North Carolina, Chapel Hill, N.C. ; prepared for U.S. Environmental Protection Agency, Office of Research and Development.