- MathOverflow, a site for questions & answers for professional mathematicians
- Math, a site for questions & answers for everybody else
- MathSciNet, a database of reviews of mathematical papers
- MRef, a checker and formatter for references to mathematical papers
- Zentralblatt MATH, another such database
- arXiv, the preprint server for math
- NUMDAM
- Göttinger Digitalisierungszentrum
- JSTOR
- Gallica, de la Bibliothèque nationale de France