The phrase open access refers to unrestricted online access to articles published in scholarly journals. Open Access comes in two forms - Gratis versus Libre: Gratis OA is no-cost online access, while Libre OA offers some additional usage rights. is similar to OA, but usually includes the right to modify the work, whereas in scholarly publishing it is customary to keep an article’s content intact by associating it with a specific author. Open access can be offered in two ways: Green OA is provided by authors publishing in any journal and then self-archiving their post prints in their institutional repository or on some other OA website. Green OA journal publishers endorse immediate OA self-archiving by their authors. Gold OA is offered by authors publishing in an that provides immediate OA to all of its articles on the publisher’s website. and Martin Lhoták, Iva Burešová.