Consultant report to Committee on Motor Vehicle Emissions, Commission on Sociotechnical Systems, National Research Council on Emissions control of engine systems [with list of references]; prepared by James E.A. John, Naeim A. Henein, Ernest M. Jost, Henry K. Newhall, David Wulfhorst, John W. Bjerklie, William J. Mclean, Charles Tobias, David G. Wilson.