Demand on researchers to justify the impact of their work outside academia is increasing. Both increasing research use in policy and measuring current use are multi-faceted problems, though there are many benefits to researchers and policymakers alike. This bibliometric study aimed to gain insight into the reference practices of Australian policymakers, and investigate how this compares to previous interview and survey studies. I analysed 4649 references from 80 government publications from 2010 to 2017 and found the most common sources of evidence were peer-reviewed journal articles, particularly open-access articles, and other Australian Government reports. This differs from previous qualitative studies which found policymakers are most likely to speak directly to colleagues for information, and far less inclined to seek out academic research. This demonstrates the inaccuracy of relying solely on quantitative or qualitative information for research impact, as well as the benefit of increased accessibility in grey literature.