Issue with citing authors


I’m trying to cite a book by three authors in a text, however I have two references with the same lead author. I think this is causing the reference to appear like this in the text:

(FloydExley and Styles, 1993) as opposed to (Floyd et al., 1993)

Does anyone have any ideas how to resolve the issue?

Thanks in advance

The problem may be due to the way the author names have been entered into the library. Please see this article for more information: