adopted through unvarying habit mon use. (used to be oral but piled into written rules)?Examples:?Warsaw-oxford Rules by the International Chamber merce (华沙-牛津规则)?The International Rules for the Interpretation of Trade Terms (INCORMS2010 国际贸易术语解释通则)?The Uniformed Customs and Practice mercial Documentary Credits (UCP600 跟单信用证统一惯例)Р9РIII Sources of international business lawРD International trade customs and usages?Influence: not law, but plays an important role.?1. as binding rules by agreed upon by the parties to the contract.?2. as interpreting or filling the gaps in the contract.?(only for usages the parties agreed to be bound or that derive from their past dealings, or the usages the party knew or ought to have known and that are regularly observed in the industry or trade involved.Р10