C:
Collection TAEF: Thomas Alva Edison Foundation Collection, 1929 - 1931 - National Archives' Archival Research Catalog description for Collection TAEF: Thomas Alva Edison Foundation Collection, 1929 - 1931 [U.S. National Archives and Records Administration (NARA)]

D:
DOE Green Energy - A portal to information about various forms of green energy, including solar, wind, bioenergy, and others [U.S. Department of Energy (DOE), Office of Science (SC), Office of Scientific and Technical Information (OSTI)]

E:
Earth Day: Selected Resources - Science Reference Guide - Finding guide from the Library of Congress, Science Reference Section [U.S. Library of Congress (LOC)]

S:
SMARTGRID.gov - A developing network of transmission lines, equipment, controls and new technologies working together to respond immediately to our 21st Century demand for electricity. [U.S. Department of Energy (DOE), National Renewable Energy Laboratory (NREL)]