R
Radcliff Institute –
The Schlesinger Library holdings date from the founding of the United States to the present and include more than 4,400 manuscript collections, 150,000 volumes of books and periodicals, and films, photos, and audiovisual material.
Read.gov from the Library of Congress
Reference Resources: Statistics
S
Scientific Literature Digital Library and Search Engine (Research Index)
Slavery In America (Gale Primary Sources)
Smithsonian Institution – Digital Library: Art and Design
T
The Library Company of Philadelphia
The SAO/NASA Astrophysics Data System
The Stony Brook Algorithm Repository
U
U.S. Census Voting & Registration Stats
U.S. Consumer Product Safety Commission
U.S. Equal Employment Opportunity Commission
U.S.D.A. National Agricultural Library Digital Collections
U.S. Presidential Inaugurations: A Resource Guide
V
Victorian Women Writers Project
W
World Health Organization, Statistical Information System (WHOSIS)