Scopus (CiteScore 2020: 1.0)
Ei Compendex
DOAJ
CrossRef
EBSCO Discovery Service
EBSCO Essentials
OCLC Discovery Services
EuroPub
MIAR
Elektronische Zeitschriftenbibliothek
Publons
UlrichsWEB
Hellenic Academic Libraries Link
Ingenta Connect
Publicly Available Content Database (ProQuest)
Advanced Technologies & Aerospace Database (ProQuest)
SciTech Premium Collection (ProQuest)
Google Scholar