Original documents
Dissertations, scientific reports and patent documents are the main documents.
The second article
Catalogue, bibliography, abstract and index are all representatives of secondary literature.
Three documents
Monographs, reviews, encyclopedias, standard documents and product samples are all members of the three major families of documents.
review article
Summative articles in periodicals and conference papers, as well as summative papers in a small number of dissertations, belong to three kinds of documents.
history of literature
Literature first appeared in Eight Books of the Analects of Confucius. Literature is books, periodicals and regulations with historical significance or research value, and it is the final expression of scientific research and technical research results.