Academic publishing is undergoing major changes, as it makes the transition from the print to the electronic format. Business models are different in the electronic environment. Since the early 1990s, licensing of electronic resources, particularly journals, has been very common. An important trend, particularly with respect to journals in the sciences, is open access via the Internet. In open access publishing, a journal article is made available free for all on the web by the publisher at the time of publication. Both open and closed journals are sometimes funded by the author paying an article processing charge, thereby shifting some fees from the reader to the researcher or their funder. Many open or closed journals fund their operations without such fees and others use them in predatory publishing. The Internet has facilitated open access self-archiving, in which authors themselves make a copy of their published articles available free for all on the web. Some important results in mathematics have been published only on arXiv.