(1966). Motivation. England: Penguin Book.
Trích dẫn kiểu ChicagoMotivation. England: Penguin Book, 1966.
Deismireacht MLAMotivation. England: Penguin Book, 1966.
Rabhadh: D'fhéadfadh nach mbeadh na deismireachtaí seo 100% cruinn i gcónaí.
(1966). Motivation. England: Penguin Book.
Trích dẫn kiểu ChicagoMotivation. England: Penguin Book, 1966.
Deismireacht MLAMotivation. England: Penguin Book, 1966.