Harvard Referencing - Cite Them Right

AUTHORS                                                                                                                                                                                
One author

Lorde, A.

Two authors

DiPietro, R.B. and Gregory, S.

Three authors

Uhrich, S., Koenigstorfer, J. and Groeppel-Klein, A.

Four or more authors - 

You can just use the first author's surname followed by et al. (in italics) within the text of your assignment.

Ryans et al. (2000)

In the referencing list you can also use et al.  where there are four authors listed.

Use the first author's surname and initial of their name followed by et al. (in italics):

Ryans, A. et al. (2000) 

There is no need to list all four authors in the reference list.