ACD's analysis of property management files needs to be permanently preserved: (1) Basic documents and materials about the property under management and important ancillary facilities and equipment, documents, records, acceptance reports and technical parameters related to the resolutions of decoration, major, medium and minor repairs. (2) Important resolutions, decisions, contract agreements, notices, records, work plans, statistical statements and related requests and reports in property management. (3) Basic information, meeting resolutions, decisions, report for instructions, records and other documents of the owners' congress and the owners' congress.