Reuse policy: a study on available reuse implementing instruments and licensing considerations

 Central IP Service of the European Commission, here. 

Consideration of Options for Open Data Licences

Irish Government Reform Unit, Department of Public Expenditure and Reform, here (Word file).

Open Government Licenses Interoperability

LAPSI Report, here. 

At the Edge of the License: Where the ODbL Ends and the Community Guidelines Begin

Blog.openstreemap.org, here.

Guides to Open Data Licensing

Theodi.org, here. 

PSI Licensing: A Conceptual Framework for EU Guidance to the Member States

M. Ricolfi, here. 

Why it's time to stop using open source licences

G. Moody, here.