- Penn Math
- Penn Math Department home page, the Penn Undergraduate Math page, the Math Major page, the Math Minor page, the Actuarial Mathe Minor page.
- Penn Library home page, Math Dept Library Resources page
- Electronic journals Penn currently subscribe. (These include back issues of many journals.)

- Archives
- The Mathematics ArXiv and its front.
- Number Theory Archive
- A list maintained by Ulf Rehmann (University of Bielefeld) of some 1800 digitized books and 120 digitized journals.
- Electronic Mathematical Archiving Network Initiative. (Frontend for several retrodigitalization projects)
- Goettinger Digitalisierungs-Zentrum. Funded by the German Research Foundation (Deutsche Forschungsgemeinschaft), this digitalization center offers a search engine. The journals you can search/download for back issues include Inv. Math.
- Numerisation de documents anciens mathematiques (Back issues of major French journals, including Publ. Math. IHES, Ann. Sc. Ecole Norm. Sup and Mem. SMF.)

- Institutions
- The American Mathematical Society home page.
- The Institute for Advanced Studies School of Mathematics home page.
- The Mathematical Sciences Research Institute home page.
- The National Center of Theoretical Sciences Division of Mathematics home page.

- Euclid on the Internet
- Number Theory links