1. Physical disability and motivation;Prosen;Can Med Assoc J,1965
2. Differential diagnosis and classification of apathy;Marin;Am J Psychiatry,1990
3. Motivation: Theory, Research and Application;Petri,1991
4. How do rheumatic diseases relate to economic potential as influenced by personal attitudes and motivation;Wolff;Pa Med,1969
5. Motivation in old age;Stewart;Physiotherapy,1975