Click on AUTHENTICATE to get the off-campus access to the electronic collection of the Library. You can check this guide or this video for more details.
Some of these electronic resources have also an institutional access via RedIris that allows the off-campus access just by selecting the name of the institution the user belongs to. After the selection, the user will have to enter the UDC´s username and password to validate the authentification. More info
Within the UDC's premises, the access to the electronic collection is free from any of the computers connected to the university network, and it is not necessary to authenticate in advance.