Regional Variations in the Potential for Energy Substitution in United States Manufacturing, by Carolyn Harper; The Determinants of Early Enrollment in the Massachusetts Special Supplemental Feeding Program for Women, Infants, and Children (WIC), by Lawrence Haddad; An Analysis of Residential Water Demand Under an Increasing Block Price Policy as Applied in the Washington Suburban Sanitary District, by Frances Hornick Smith; Optimal Timing of Pesticide Application for the Control of the Colorado Potato Beetle, by Jean-Louis Zeller