Useful links

Ciência Aberta -
DOAB Directory of Open Access Books -
DOAJ Directory of Open Access Journals -
Networked Digital Library of Theses and Dissertations (NDLTD) -
OpenAIRE Explore -
OpenDOAR The Directory of Open Acces Repositories -
PubMed -
ROAR Registry of Open Access Repositories -
Sherpa Romeo -
SPARC (the Scholarly Publishing and Academic Resources Coalition) -
UC Open Science -
Zenodo -