When there are three or more writers, just the first author's surname is included in the text, and the remainder of the list is abbreviated with "et al" (Latin for "and others"). You include all of the writers in your reference list (up to 20).
If there are fewer than three authors, then each one of them has a separate entry on the reference list. These entries are listed in alphabetical order by last name.
In both cases, it is necessary to provide the full title of the work being cited. If the work has multiple titles, then list each one in turn. Use periods as separators between titles when necessary.
For example, if you were citing two books by John Doe, then their titles would be listed as "Book 1" and "Book 2". Their respective reference lists would look like this:
"Book 1" by John Doe and "Book 2" by Joe Public.
It is important to make sure that each entry on the reference list is related to the work being cited. For example, if you were citing a book by John Doe and another book by the same author, then both names would go into the reference list. Also, if you were citing a book by John Doe and an article by him, then only his name would go into the reference list because the article is not related to the book.
For works with three or more authors, the in-text citation is now abbreviated beginning with the first citation. Only the first author's name and "et al." are included. In the reference entry, surnames and initials for up to 20 writers (rather than 7) should be supplied. If the work has more than 20 contributors, list them all with their respective roles.
Citing multiple works by the same author is known as "double-counting" or "oligocounting". While this does not produce an error when using single-author works, it can lead to inaccurate results when calculating percentages or comparing numbers between studies. To avoid these problems, even when there are only three or four authors in a study, each time you refer to this writer, include the word "and" before the surname(s) of any other authors who have written on the topic.
So, the full citation for this article would be: Et Al., "The Effects of Monetary Policy on Asset Prices," The Journal of Economic Perspectives 27, no. 3 (2013): 83-106.
Et Al., "The Effects of Monetary Policy on Asset Prices," Journal of Economic Perspectives 27, no. 3 (2013).
You may use "et al." from the first mention if there are at least six writers. In all circumstances, use the first author's last name followed by "et al." in your in-text citation.
If a document contains six or more writers, just replace the last name of the first author with "et al." from the first to the final citation. Thomas and colleagues are an example.
Cite the first name provided in the source, followed by et al., if there are four or more authors. No matter how many writers or editors there are, their names will all be mentioned in your reference, as illustrated below.
Lets say that John, Jane, and Michael are three authors of a book. They signed the book with their first names only, but for the record their full names are John Leonard Michaels.
When you use this book in a paper, refer to them as "John, Jane, and Michael's book". This makes it clear that you are using an edited work and not just writing about something you found on the internet.
In general, when citing multiple sources, make sure to give each one of them a unique label. That way, readers can see for themselves which parts are most relevant to their papers.
Good luck with your research!