Cognitive and motivational aspects of action : selected revised papers XXIInd international congress of psychology Leipzig, GDR, July 6-12, 1980 / ed. by Winfried Hacker, Walter Volpert and Mario von CranachCognitive and motivational aspects of action / ed. by Winfried Hacker, Walter Volpert ... [et al ; contrib. by A.K. Balotowa ... et al.]