Παραπομπή APA

Woolley, S. (1948). Power of concentration. Isaac pitman & Sons.

Παραπομπή Chicago Style

Woolley, S.F. Power of Concentration. London: Isaac pitman & Sons, 1948.

Παραπομπή MLA

Woolley, S.F. Power of Concentration. Isaac pitman & Sons, 1948.