Open Access and libraries

When we talk about open access (OA) we often referring to permanent, free online access to full text of all refereed research journal articles. Of which 2.5 million articles a year are published in 24,000 refereed journals across all disciplines, languages and nations.http://www.zim.mpg.de/openaccess-berlin/berlindeclaration.html

 That are free of all restrictions on  access and free of many restrictions on use, example  certain copy right and license restrictions.Open access can be applied to all forms of published research output, including peer reviewed and non peer- reviewed journal articles.

There are two types of open access which often spoken about which is gratis open access and libre open access.