Q. How would I refer to a book/journal article with more than three authors in my reference list?

Unlike the in-text citation (where you would only list the first author followed by et al.) in your reference list you need to list all the authors.  Separate the authors with a comma but the last name should be preceded with an 'and' e.g.

Alberts, B., Bray, D., Hopkin, K., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2014) Essential cell biology, 4th edition. New York, USA: Garland Science.

See Referencing Guide.