1. Google Scholar.

2. Index Copernicus International (ICV 2019 = 96.82)

3. Europub (Directory of Academic and Scientific Journals)     

4. Navel Academic

5. Dimensions

6. Mendeley (Elsevier)

7. ScienceGate   

8. Sciete

9. Altmetric

10. Kudos

11. Crossref

12. ROAD

13. CORE

14. Base