Freeman, S. (2002). Biological science. Prentice Hall.
Cita Chicago (17th ed.)Freeman, Scott. Biological Science. Upper Saddle River, New Jersey: Prentice Hall, 2002.
Cita MLA (9th ed.)Freeman, Scott. Biological Science. Prentice Hall, 2002.
Atenció: Aquestes cites poden no estar 100% correctes.