AccessOn (Korea)

ASOS Index, 

BASE (Bielefeld Academic Search Engine)

CROSSREF

Dimensions

EuroPub

Google Scholar, 

Ideal online , 

Index Copernicus, 

OpenAIRE

OUCI - The Open Ukrainian Citation Index

Paperity

Publons

ROAD (Directory Open Access Scholarly Resources), 

Scilit

scite_

SemanticScholar

Wizdom

Worldcat

World Catalogue of Scientific Journals ,