In the digital environment, journal subscriptions and book purchases as we know them from the print environment are replaced by the concept of granting access to publications just for a given time. The library does not ``own'' the items, but ``leases'' access to the documents. The detailed access and usage conditions are described in contracts between publishers and libraries. These contracts, typically called license agreements, regulate, for instance, for how long the library has access to the publication, what users and librarians are allowed to do with it, how many simultaneous users are granted access, and how often the publication can be viewed, printed or otherwise used. License agreements must also determine what happens after the contract terminates. Since it is the nature of leased material that it remains physically with the provider, many librarians fear that they will be left without anything when a leasing contract ends.
As a result, publications requested by our users more and more often will not be available in our libraries, but will have to be obtained from external sources. No standard mode for access to back volumes of publications is yet being applied, and terms and conditions vary from publisher to publisher. It is possible, however, that libraries will have to pay twice (or more often) for the same product - once while a contract lasts, and again after cancellation or termination of a title if a user needs a particular article from the timeperiod when the library subscribed.