The Internet has had a significant effect on the availability and delivery of reference services. Many reference works, such as the "Encyclopædia Britannica", have moved entirely online, and the way people access and use these works has changed dramatically in recent decades. The rise of search engines and crowd-sourced resources such as Wikipedia have transformed the reference environment. In addition to the traditional reference interview, reference librarians have an increasing role in providing access to digitized reference works (including the selection and purchase of databases not available to the general public) and ensuring that references are reliable and presented in an academically acceptable manner. Librarians also have a role in teaching information literacy, so that patrons can find, understand and use information and finding aids like search engines, databases and library catalogs: for instance, patrons who lack access to expensive academic subscriptions can be taught to Unpaywall to access open access literature easily.