1. Journal TOCs (Free Table of Content for Individual researchers from more than 25000 scholarly Journals)
2. Mendeley (A free reference manager and PDF organizer and academic social network from Elsevier)
3. Zotero (Free Bibliographic and PDF Organizer from George Mason University)
4. Journal Ranking (Based on Scopus, Elsevier)
5. Open Rev (Open Science reviewing tool from Harvard University)

Academic Search Engine

1. BASE (Bielefeld Academic Search Engine)
2. Google Scholar
3. Microsoft Academic Search