Ridley, M., & Grafen, A. (1981). ARE GREEN BEARD GENES OUTLAWS.
Cita Chicago (17th ed.)Ridley, M., i A. Grafen. ARE GREEN BEARD GENES OUTLAWS. 1981.
Cita MLA (9th ed.)Ridley, M., i A. Grafen. ARE GREEN BEARD GENES OUTLAWS. 1981.
Atenció: Aquestes cites poden no estar 100% correctes.