1. Constitutional Acts Affecting the EU
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Primary law
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European Convention on Human Rights
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Other international treaties
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Member States' constitutions
The EU legal order is affected not only by the national legal orders, but also other regional and international regimes, such as the European Convention on Human Rights and the Charter of the United Nations. Thus, one can talk about interaction between the EU constitutional norms, Member States' constitutions, and international treaties. As one can also distinguish between economic, social, security-related, etc. sub-units within this constitutional interaction, one can talk about constitutional pluralism in the EU. See: C. Kombos (2010) „The Esoteric Dimension of Constitutional Pluralism: EU’s Internal Constitutional Sub-units and the Non-symbolic Cumulative Constitution“ in P. J. Birkinshaw, M. Varney (eds.), The European Union Legal Order after Lisbon (Austin, Boston, Chicago, New York, The Netherlands: Kluwer) 291-323.
Please, try also to find different EU constitutional acts. You could start with the primary law of the EU that can be found from the EUR-Lex. In addition to primary law, EUR-Lex also contains secondary law of the EU. As for the primary law, please, find the Treaty on European Union (TEU) and the
Treaty on the Functioning of the European Union (TFEU). The link to EUR-Lex: http://eur-lex.europa.eu/en/treaties/index.htm
The European Convention on Human Rights is one of the important treaties concluded under the framework of the Council of Europe. You can access the Council of Europe's Treaty Office here: http://conventions.coe.int
Other international treaties of the EU may be found from EUR-Lex, Agreements Database of the Council of the European Union, and Treaties Office Database of the European Commission: 
http://eur-lex.europa.eu/en/accords/accords.htm

http://eur-lex.europa.eu/en/accords/accords.htm
Member States' constitutional laws, but also other legal acts may be found from N-Lex: http://eur-lex.europa.eu/n-lex/index_en.htm