- AceMap – Shanghai Jiao Tong University
- AMiner – Tsinghua University
- CiteSeerX – Penn State University
- EasyChair conference system
- Eigenfactor Project – University of Washington
- Microsoft Academic – Microsoft Research
- Semantic Scholar – Allen Institute for Artificial Intelligence
- SoScholar – Chinese Academy of Science
- Torvik Research Group – University of Illinois
- VizioMetrics – University of Washington