| 1 | H.W. Wilson | [Link] |
| 2 | EBSCO | [Link] |
| 3 | Türk Eğitim İndeksi | [Link] |
| 4 | University of Regensburg Library | [Link] |
| 5 | University of Washington Library | [Link] |
| 6 | University of Hamburg Library | [Link] |
| 7 | University of Berlin Library | [Link] |
| 8 | University of Regensburg Library | [Link] |
| 9 | ACER | [Link] |
| 10 | University of Bremen Library | [Link] |
| 11 | Clausthal University of Technology Library | [Link] |
| 12 | WorldCat | [Link] |
| 13 | Scientific Indexing Services | [Link] |
| 14 | University of Leipzig Library | [Link] |
| 15 | Open Academic Journals Index (OAJI) | [Link] |
| 16 | International Journal Impact Factor | [Link] |
| 17 | ERIC | [Link] |