When a paper quotes literature, it is necessary to indicate the source of the quoted content. The following are some commonly used methods to mark cited documents: \r\n 1. Direct quotation: If you quote others directly, you need to add the author's name, year and page number to the quotation, and enclose the quotation in quotation marks. \ r \ nFor example, according to Jones (20 15, p.25), music has an important influence on the development of the human brain, and "Mirica has a profound influence on the development of the human brain" \ r \ n 2. Indirect quotation: If you don't directly quote the original text, but express other people's opinions or research results in your own language or writing, \ r \ For example, students' learning motivation has an important influence on their academic performance (Smith, 20 10). \r\n3. Multiple references: If multiple references are cited at the same time, you can connect different documents with semicolons or "and" and arrange them alphabetically according to the author's surname. \ r \ For example, many studies show that the human brain's perception of music is closely related to its emotional experience (Jones, 2015; Smith, 2010). \ r \ nIt should be noted that academic norms and requirements should be strictly observed when quoting documents, so as to avoid copying and plagiarizing other people's works. At the same time, when marking the source, the author's name, year, page number and other information should be accurately and clearly marked so that readers can refer to the original text. Among the references, all the cited documents should be listed and typeset according to certain formats and requirements.