For example, a psychologist will be aware of pavlovian conditioning, so you do not need to reference that if it from your own head. There are a number of ways in which you can reference the source, but most are based upon variations of MLA and APA style.
Check with your supervisor which exact technique you should be using, and be consistent.
Referencing is an essential part of writing any research paper, so err on the side of caution.
Common knowledge does not need to be referenced, and you can assume that any reader is fairly knowledgeable about the field.
The MLA style in text citation has two variations, the author/page number, although the modern trend is for author/year/page number, such as If there are more than two authors listed, then the usual standard is to mention both (Sargeant & Mc Evoy, 2008).
For multiple authors, it is usual to mention them all the first time, but to use 'et al.' afterwards.
For example, This makes it clear that you could not access the original work, and that you correctly attribute the original findings to the researcher who actually performed the initial research.
A few standards, such as Chicago style and the Council of Biology Editors (BCE) use a footnote numbering system, where a number is used and cross-referenced with the endnote section and bibliography: It is always best to over cite, and avoid accusations of plagiarism, but there are a few times that citation is not necessary.
There are a few variations, especially with electronic information, but they all follow the same basic structure.
If the author has written more than one paper in the same year, then you can use an alphabetical appendix: The other difficulty is when there is no author mentioned, and the source was written by an organization.