Even if they retain the copyright to an article, most journals allow certain rights to their authors. These rights usually include the ability to reuse parts of the paper in the author's future work, and allow the author to distribute a limited number of copies. In the print format, such copies are called reprints; in the electronic format, they are called postprints . Some publishers, for example the American Physical Society , also grant the author the right to post and update the article on the author's or employer's website and on free e-print servers, to grant permission to others to use or reuse figures, and even to reprint the article as long as no fee is charged.  The rise of open access journals, in which the author retains the copyright but must pay a publication charge, such as the Public Library of Science family of journals, is another recent response to copyright concerns.