Which license should I choose for publications, research data or source code?

Helsinki University Library has published a license guide.

Shortly:

“In general, the University of Helsinki recommends CC BY – license for sharing publications, unless there are other recommendations by the publisher.”
“For sharing of research data The University of Helsinki recommends CC 0 – license, where the author gives up all copyrights in order to advance open science.”
“For sharing of source code the University of Helsinki recommends MIT- or GNU-GPL (v2) –licenses which have been developed for just this purpose”

Please, find further information from Open Access: License Guide: http://libraryguides.helsinki.fi/oa/eng/license