I can actually think of a couple places off the top of my head to reference in support of this research:
Please know that there are hundreds if not thousands of other companies that blatantly discriminate against black workers and pay them less than whites. So all in all maybe “sounding black” is the reason? or just simply “being black”? According to the research, God help you if you’re “southern”.
The complete document for this study can be found here.