what is the meaning of et al in referencing

Here is how this would look for a source authored by Sookochoff, Lai, and Bakke published in 2017:
For a work with one or two authors, include the name(s) in every citation. Here is how this could look:

PhD in English, Georgia State University
This article was co-authored by Michelle Golden, PhD. Michelle Golden is an English teacher in Athens, Georgia. She received her MA in Language Arts Teacher Education in 2008 and received her PhD in English from Georgia State University in 2015.

showing that you want to listen is one of the things you can do quick to change the way your department feels and to develop strong bond between you and your colleagues (p. 39).
Morris, S., Willcocks, G, and Knasel, E. (2002) How to lead a winning team. London: Prentice-Hall.

To be made up of:

• Authors.
• Year of publication (in round brackets).
• Title of article (in single quotation marks).
• Title of journal (in italics and capitalise first letter of each word in title, except for linking words such as and, of, the, for).
• Volume number.
• Issue number (in brackets).
• Page numbers of article preceded by p. for one page, pp. if multiple pages.
• doi: if available.

0800 373 7550 or 966 for 24-hour emergency telephone number.
+64 9 373 7999 for telephone receptionists, or
+64 9 373 7599 and the appropriate extension.

References:

http://www.wikihow.com/Use-Et-Al
http://don.libguides.com/c.php?g=658927&p=4651394
http://libguides.ioe.ac.uk/c.php?g=482485&p=3299802
http://www.cite.auckland.ac.nz/5_3.html
http://www.bibme.org/citation-guide/apa/