Rumpel, this axe in the Pittrivers museum Oxford is assigned to the Nuer but as you can see from the ethnic map link this is rather a broad statement. Different ethnic groups may also carry very similar stvle of axe.
http://southernsudan.prm.ox.ac.uk/de...946.8.91_b.jpg
Map
http://www1.american.edu/ted/ICE/ima...groups-map.jpg