18 OA reference titles (as of Nov. 2021). In total, Brill today publishes more than 360 journals and 2,000 new books and reference works each year as well as a large number of databases and primary source research collections.

Oxford University Press publishes many valuable reference resources. The overwhelming majority of the content is behind a paywall (libraries usually subscribe), however this list of OA entries from various OUP titles might prove to be useful in and of itself, but it could also lead researchers to a dictionary or encyclopedia that will fill an information gap.