Write the year of publication after the author(s)’ name(s) in the brief citation. In the ATU Harvard style, we display it like this:
(Molloy, 2023).
If the source you are referencing is missing a year of publication, use the words 'no date' instead of a year in your in-text citation. In your Reference list, use the words 'no date' in place of the year of publication.
The rest of the reference should follow the usual style for the type of source you are citing.
(Molloy, no date).
Molloy, M. (no date) Rolling back time. Galway: Mars Press.
If the date can be established, but only approximately you should use c.
O’Dowd (c.2010) has found that….