"Double check by one person" means that after a document is written, reviewed and signed by one person, it needs another person to check and confirm it for the second time. Confirmed, signed and sealed by the person. This method can reduce the error probability caused by human factors and enhance the accuracy and reliability of documents.

"Double signature" means that the document needs to be signed by two or more authorized persons respectively, so as to show the understanding, approval and agreement of the document content and agreement. This method can avoid the risks caused by improper operation or problems of a single authorizer, and enhance the legitimacy and effectiveness of the document.