If your research paper would benefit from adding a graph to display data that would be difficult to explain otherwise, I recommend using gapminder to produce it:
For information on how to cite maps, images and graphs, you’ll have to be creative. The main thing is that you want to give credit where credit is due, and tell me (your reader) how to find the source of the information.
Paintings, Sculptures, Radio Broadcasts– find info on how to cite those here:
graphs and maps: