• Google Scholar – Academic articles, research papers, and citations. (scholar.google.com)
• Pew Research Center – Nonpartisan research and data reports. (pewresearch.org)
• CliffsNotes – Study guides and summaries. (cliffsnotes.com)
• NovelGuide – Literature summaries and analysis. (novelguide.com)
• Math.com – Tutorials, problem-solving, and learning resources for math. (math.com)
• Wikipedia – General reference and encyclopedia. (wikipedia.org)
• The Free Dictionary – Language definitions, synonyms, and references. (thefreedictionary.com)
• Answers.com – Community-driven knowledge and Q&A. (answers.com)
• Difference Between – Comparisons and differences between concepts. (differencebetween.com)
• Refdesk – Online reference and fact-checking portal. (refdesk.com)
• Project Gutenberg – Free access to classic literature and ebooks. (gutenberg.org)
• Library of Congress – National library collections and digital archives. (loc.gov)
• Smithsonian – Museum collections, history, and research. (si.edu)
• National Geographic – Educational resources in science, history, and culture. (nationalgeographic.com)
• PBS LearningMedia – Free classroom-ready educational media. (pbslearningmedia.org)
• Bank of America – Museums on Us – Free museum entry program for cardholders. (about.bankofamerica.com)