the principle of voluntary exchange 自愿交换原则 ; 自愿的原则交换
principle of voluntary participation 自愿互利原则
principle of voluntary nationality 国籍自愿原则
A free enterprise economy is based on the principle of voluntary association and exchange.
私有经济的基础是自发联合和交换。
Third, we have adhered to the principle of voluntary participation farmers, absolutely refrain from forcibly assessed.
第三，坚持了农民自愿参加的原则，绝对不搞强行摊派。
Since the creation of copyright works from the date of completion of production in China to implement the principle of voluntary registration.
著作权自作品创作完成之日起产生，在中国实行自愿登记原则。
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