- European Union Studies Center , ( 2001) , Principles of European Contract Law( PECL)-
- European Group on Tort Law , ( 2005) , Principles of European Tort Law
-Frey, Martin A. & coworkers, ( 2007), An Introduction to the Law of Contracts, New York, West Legal Studies (Thomson Learning), 3thed
- Honnold, John, ( 2009 ), Uniform Law for International Sales under the 1980 United Nations Convention, Pace Law School Institute of International Commercial Law, 2thed
- Huber, Peter & Mullis, Alastair, ( 2007), The CISG A new textbook for Student and practitioners, Germany, Sellier.European law publishers
- Institute of International Pour Iunification du Drout prive ( UNIDROUT ) ,( 2004) , Principles of International Commercial Contracts
- Lando, Ole & coworker, (2019), The Principles of European Contract Law, Parts 1 and 2, prepared by the Commission on European Contract Law, The Hugh, London, Kluwer Law International
- United Nations Commission on International Trade Law , (1980) , United Nations Convention on Contracts for the International Sale of Goods
- UNCITRAL Digest of Case Law on the United Nations Convention on Contracts for the International Sale of Goods, United Nations, New York (2012), Retrieved from the website address: http://www.uncitral.org/.