That depends on the theoratical foundations of your study as well as on research questions of the study.Are you interested in comparing the differences in their budgeting, or the factors that shape their budgeting behaviors .There are so many other aspects that can be studied.so firstly you are supposed to clearly define your topic or in other words operationalize your study.

What is the context of the budgeting?

GRB initiatives seek to create a direct linkage between social and economic policies through the application of a gender analysis to the formulation and implementation of government budgets. A gender analysis can also demonstrate the ways in which social institutions that are seemingly “gender neutral” do in fact bear and transmit gender biases. Gender budget analyses can be applied to gender specific expenditures, expenditures that promote gender equity within the public service and general or mainstream expenditures

If this is a macro-level public policy, public sector budget study then there are lots of sources to consider: