References and notes can be repeated.

Supplementary information:

References are a part of the paper, and notes are a part of the text, which have different functions. Notes in the text are supplements to the text, including confirmations. Write references at the back of the paper, indicating which books you refer to in your paper are explanations of the details in the article, which are not the same as noun explanations, but similar to noun explanations, but not exactly the same. Reference refers to the materials that are referenced, borrowed and cited in the process of writing a paper, as well as the sources of the materials. Comments are usually at the bottom of every page, but they can also be placed at the end of the article. References must be at the end of the article.

In addition, the number symbols are different, so we should pay attention to distinguish them.