Cita APA (7th ed.)

Gibson, D. P. (1969). The 30 billion negro. MacMillan.

Cita Chicago (17th ed.)

Gibson, D. Parke. The 30 Billion Negro. Londres: MacMillan, 1969.

Cita MLA (9th ed.)

Gibson, D. Parke. The 30 Billion Negro. MacMillan, 1969.