What is the abbreviation used for more than one author when citation?

The abbreviation used for more than one author when citing depends on the style guide you are using. Here are the most common ones:

* "et al." (Latin for "and others"): This is the most common abbreviation and is used in many styles, including APA, MLA, and Chicago. It's used when there are three or more authors. For example:

"Smith et al. (2023) found..."

* "and colleagues" or "and collaborators": These phrases can be used instead of "et al." in some styles, particularly if you want a more formal or specific tone.

* List all authors: Some styles, like the ACS style, require you to list all authors until there are six or more. After six, "et al." is used.

Important Note:

* Always check the specific style guide you are using for its exact rules on citing multiple authors.

* Be consistent throughout your work.

Hope this helps!