A、投邮生效原则
B、签订书面合约原则
C、口头协商原则
D、到达生效原则

A、documentarycreditmeanspaymentagainstdocumentinsteadofagainstgoods
B、allthedocumentarycreditsareoperatedthroughbanks
C、thebuyersisnotrequiredtopayforthegoodsuntilthearrivaloftherelevantshippingdocuments
D、thedocumentstransfertitletothegoods