The OAPEN Library contains freely accessible academic books, mainly in the area of humanities and social sciences. OAPEN works with publishers to build a quality controlled collection of open access books, and provides services for publishers, libraries and research funders in the areas of deposit, quality assurance, dissemination, and digital preservation.
Paperity is the first multi-disciplinary aggregator of peer-reviewed Open Access journals and papers, "gold" and "hybrid". ultimate goal is to aggregate 100% of Open Access literature, published in any place around the world, in any field of research.
BASE is a multi-disciplinary search engine for scientifically relevant web resources harvested from OAI scientific repository servers. In addition to OAI metadata the library indexes selected web sites and local data collections, which can be searched via one single search interface in one go. created and developed by Bielefeld University Library. BASEsearch
Peter Suber, Open Access to Science and Scholarship. News and discussion on the migration of print scholarship to the internet and efforts to make it available to readers free of charge.