Referencing is acknowledging the intellectual work of others in written assignments by citing sources. It is important for several reasons, including showing supporting evidence, adding credibility, and avoiding plagiarism. The Harvard referencing system is introduced, which cites sources in-text with the author's last name and date, and includes a reference list with full citations. The reference list is placed at the end of the assignment in alphabetical order by author's last name. Different source types like books, journals, and electronic sources are demonstrated for the reference list format. Proper referencing is important for academic integrity and can impact assignment marks.