Sally Hewitt. (2000). Life Cycles (Discovering Nature). Copper Beech.
Cita Chicago (17th ed.)Sally Hewitt. Life Cycles (Discovering Nature). Copper Beech, 2000.
Cita MLA (9th ed.)Sally Hewitt. Life Cycles (Discovering Nature). Copper Beech, 2000.
Atenció: Aquestes cites poden no estar 100% correctes.