Cita APA (7th ed.)
Cothran, H. Energy Alternatives: Opposing Viewpoints. Greenhaven.
Cita Chicago (17th ed.)
Cothran, Helen. Energy Alternatives: Opposing Viewpoints. San Diego, EUA: Greenhaven.
Cita MLA (9th ed.)
Cothran, Helen. Energy Alternatives: Opposing Viewpoints. Greenhaven.
Atenció: Aquestes cites poden no estar 100% correctes.