Citations
ChatDOC
Chat with your documents and click through to the passage behind each answer
Gemini Notebook (formerly NotebookLM)
Source-grounded research notebooks with audio, video and slide summaries
Mendeley
Elsevier's free reference manager, with paid AI tools for your own library
Perplexity AI
Answer engine that cites its sources, now with a browser and an agent
Perplexity Pages
Perplexity's cited research pages, retired pending a promised rebuild
Perplexity Pro
Perplexity's $17-a-month tier: model choice, Deep Research and Computer
Academic search that ranks papers and experts by influence within your field
Open-source AI search with citations, plus paid Pro and Max plans
Semantic Scholar
Free AI-assisted academic search across 200M+ papers, from Ai2
Stanford's open-source research prototype that drafts cited reports
Zotero
Free, open-source reference manager from a nonprofit