The relation between government debt and economic growth in developing country

My dissertation is the relation between government debt and economic growth in developing country.. i need to give 8 country.. using irf, var or vecm, unit root test, cointegration test. The variable is government debt data, goverment expenditure, unemploeyment, gdp growth in %, export riil data, export persentase to gdp, export growth %, debt to gdp ratio..each data is the last 25 years.I need more methodology and variable to be more accurate