The EC’s State aid rules apply to any subsidies granted by the Member States of the EU
Finding commentary on SOLO
Subject searches to use in SOLO to find commentary in books (both e- and print)
Subsidies Law and legislation + European Union countries
Government aid -- Law and legislation + European Union countries
Economic assistance, European -- Law and legislation
Subsidies - European Union countries
In addition to subject searches using subsidies or government aid, it is also worth trying
World Trade Organization -- Rules and practice
and/or Foreign trade regulation
and/or International trade