Referencing a figure/graph
A figure or graph can be referenced in much the same way as an image whose creator is uncredited—i.e., by referencing the source in which the graph appears. For example:
Author, A., Author, B., Author, C., Author, D., & Author, E. (Date). Title of journal article: Subtitle in sentence case. Title of Journal in Italic Title Case, volume(issue number), page range of article.
Reference list entry
Edwards, R., Peace, J., Stanley, J., Atkinson, J., Wilson, N., & Thomson, G. (2012). Setting a good example? Changes in smoking prevalence among key occupational groups in New Zealand: Evidence from the 1981 and 2006 censuses. Nicotine & Tobacco Research, 14(3), 329-337.
Figure 1 shows the correlation between...
... occupational groups' smoking habits (Figure 1).