Write a paper on ancient poetry, quoting ancient poetry, and you don't need to indicate it in the references. The reference cited in a paper refers to the whole reference or reference to a book or paper in the process of academic research. Literature information resources include: books, serial publications (periodicals, newspapers, etc. ), brochures, papers, patents, standards, meeting minutes, government publications, etc. The National Standard Document Types and Document Carrier Codes (GB3469-83) classifies documents into 26 categories according to practical standards, namely: monographs, newspapers, periodicals, conference proceedings, compilations, dissertations, scientific reports, technical standards, patent documents, product samples, Chinese translations, manuscripts, reference tools, retrieval tools, files, charts, ancient books and so on.