Mathematical Reviews has a program for extending the reach of the database to include material from the various retrodigitization projects by libraries, institutions, and publishers. Many of these fall under the umbrella of the World Digital Mathematics Library (WDML), which seems to be becoming known as the Global Digital Mathematics Library, sponsored by the IMU. The origin of the WDML is Ulf Rehmann‘s DML, hosted at the University of Bielefeld. Items in MathSciNet that are part of this program are flagged with the icon 
. Incorporating a digitized journal into the DML means that a search in MathSciNet can return items from the digitized journal, even if it predates the beginning of Mathematical Reviews.
For example, if you search for Cayley as an author and ask to have “quartic” in the title of the paper:
The results begin as
You can see one of the newest stars of the program in the first four items: the Journal für die Reine und Angewandte Mathematik, also known as Crelle’s Journal. Last week, the staff at Mathematical Reviews completed the uploading and checking of the data for Crelle’s Journal. The “checking” took a long time since the journal has been around for a long time, with the first issue published in 1826. The digitization was done by de Gruyter, who also provided us with the data.
Two other important journals that started in the 19th century also show up in the list of Cayley’s work on quartics: Mathematische Annalen and the Proceedings of the London Mathematical Society.
There is another wonderful thing hidden in this list of results. In all of the items, there is an active link marked Article. If you click on that, you go to the actual article by Cayley! Indeed, that is a major reason for the effort! By incorporating Crelle’s Journal, Math. Annalen, Proc. London Math. Soc., and many others into MathSciNet, you can now search the old literature and, in a matter of a couple of clicks, end up at the original article. You can read more about the program on the MathSciNet help page. Note that clicking on the icon brings you to the help entry on the DML.
Meanwhile, if you want to go exploring collections of digitized publications in the mathematical sciences on your own, you can go to the AMS Digital Mathematics Registry, which is maintained by Mathematical Reviews staff.
How is that for backward progress?
