1. Science and Technology Index 

2. Directory Of Open Access Journals

3. Crossref

4..Google Scholar

5. Garba Rujukan Digital (Garuda)

6.Dimension

7.ICI Index Copernicus International

8. EBSCO Open Science Directory

9. Indonesia OneSearch by Perpusnas

10. Public Knowledge Project-Index

11.Directory Of Research Journals Indexing

12. Directory of Open Access Scholarly Resources (ROAD)

13. WorldCat

14. University of  OXFORD

15. Bielefeld Academic Search Engine (BASE)

16. Harvard Library

17. Scilit

18. OpenAIRE

19. Journal TOCs

20. BU Libraries Search

21. Sherpa/Romeo

22.Leiden University Libraries

23.Copac Jisc

24. Collective Goods Research & Explore (CORE)

25. The University Of Sheffield

26. Stanford University

27. Nelson Mandela University

28. Vancouver Public Library

29. University Library