Παραπομπή σε μορφή APA (7η εκδ.)

Wolff, J. Focus: Use the power of targeted thinking to get more done : Use the power of targeted thinking to get more done (2.). Pearson Education UK.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Wolff, Jurgen. Focus: Use the Power of Targeted Thinking to Get More Done : Use the Power of Targeted Thinking to Get More Done. 2. Pearson Education UK.

Παραπομπή σε μορφή MLA (8th εκδ.)

Wolff, Jurgen. Focus: Use the Power of Targeted Thinking to Get More Done : Use the Power of Targeted Thinking to Get More Done. 2. Pearson Education UK.