Robert C Beck. (1990). Motivation: Theories and principles. PHI.
Chicago Edition CitationRobert C Beck. Motivation: Theories and Principles. New Jersey: PHI, 1990.
ציטוט MLARobert C Beck. Motivation: Theories and Principles. PHI, 1990.
אזהרה: ציטוטים אלה לעיתים לא מדויקים ב 100%.