EUR-Lex's analytical register on Taxation
The European Union's register of all English language EU legislation relating to Tax harmonisation.

Taxation index of the Directorate-General for Taxation and the Customs Union
Index of links on the Taxation programmes of the European Commission. Includes speeches, public and closed consultations and Commission proposals.

Corporate Tax Harmonisation in Europe
A report from the Institute for Fiscal Studies looking at the long term trends in regard to harmonisation of corporate taxes in the EU.