Cita APA (7th ed.)

Keagle James M & Longdom Publishing. Thinking Ahead.

Cita Chicago (17th ed.)

Keagle James M i Longdom Publishing. Thinking Ahead.

Cita MLA (9th ed.)

Keagle James M i Longdom Publishing. Thinking Ahead.

Atenció: Aquestes cites poden no estar 100% correctes.