Willis, S. L. (1990). Maintaining professional competence: Approaches to career enhancement, vitality, and success throughout a work life. Jossey-Bass Publishers.
Citace podle Chicago (17th ed.)Willis, Sherry L. Maintaining Professional Competence: Approaches to Career Enhancement, Vitality, and Success Throughout a Work Life. San Francisco: Jossey-Bass Publishers, 1990.
Citace podle MLA (9th ed.)Willis, Sherry L. Maintaining Professional Competence: Approaches to Career Enhancement, Vitality, and Success Throughout a Work Life. Jossey-Bass Publishers, 1990.
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