MR Lookup is a tool for verifying references and for adding links to MathSciNet, in many cases indirectly adding links to original papers.

The American Mathematical Society believes that using MathSciNet for linking to original papers fosters linking of the electronic literature, now and in the future. Authors or publishers can add a permanent link to the MathSciNet entry for each reference in a published paper using a standard format and tools provided free of charge by the Society. The Society in return will add links from MathSciNet to original papers whenever possible and keep those links up to date in the future. Readers are therefore able to navigate from any reference in two clicks, first to the MathSciNet entry and then to the original paper (when it is available). Soon, even users without a subscription to MathSciNet will be able to access original articles in this way.

There are a number of advantages to this linking scheme:

• Building links for authors and publishers of source articles is simpler, requiring a single format and tools that are provided free of charge.
• Building links allows authors and publishers to verify bibliographic data for journal articles using the Mathematical Reviews database. This results in more consistent references.
• Readers obtain two kinds of information — a review (or summary) and the original article. In many cases, the review may be more helpful than the article, and when the original article is unavailable to the reader, a review may be a good substitute.
• Publishers of target articles need take no action to enable linking (except to maintain a systematic format to access their journal articles).
• The older literature from the past 60 years becomes part of the web immediately through reviews of the papers. As these older articles become available online, new links will be added automatically, without any action by source publishers.

The new MR Lookup tool is a first step in implementing these links, making it easy for authors to insert links to reviews in standard form. We hope the community will make a commitment to add these links to all new papers, and will encourage publishers to include links in all electronic literature.