David Guetta's single "Hey Mama" (feat Nicki Minaj) is built around a sample of "Rosie"--a recording of Black Inmates at the Mississippi State Penitentiary aka Parchman Farm, produced by John and Alan Lomax in 1947. The employ of the inmates voices highlights the myriad (a very large number) ways that their labor--primarily picking cotton--was exploited.
Source: blogspot.com