- Google Scholar, USA
- SSRN – Elsevier, USA
- Publon, USA
- SherpaRomeo
- WorldCat, USA
- HOLLIS, Harvard University, USA
- Elektronische Zeitschriftenbibliothek (EZB), Germany
- Berlin Social Sciences Center, Germany
- Asos Indeks, Turkey
- World Catalogue of Scientific Journals (WCOSJ)
- Academia
- Academic Resource Index – ResearchBib
- Advanced Science Index, Germany
- Bielefield Academic Search Engine (BASE), USA
- Cosmos Impact Factor
- Directory of Research Journal Indexing (DRJI)
- Mendeley – Elsevier, Netherlands
- Eurasian Scientific Journal Index (ESJI)
- EuroPub
- General Impact Factor
- Index Copernicus, Poland
- International Institute of Organized Research (I2OR)
- International Scientific Indexing (ISI), UAE
- Journal Index
- Leipzig University, Germany
- OpenAire
- Refseek*
- Researchgate
- Root Indexing, India
- Scientific Indexing Services (SIS), USA
- Scientific Journal Impact Factor (SJIF)
- Scilit
- Scimatic, Turkey
- Scribd , USA
- TIB, Germany
- Turkish Education Index, Turkey
- University of Hamburg
- University of JOS Nigeria, Institutional Repository, Nigeria
- World Energy Council
- Zenodo