Παραπομπή σε μορφή APA (7η εκδ.)

Willis, S. L. (1990). Maintaining professional competence: Approaches to career enhancement, vitality, and success throughout a work life. Jossey-Bass Publishers.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Willis, Sherry L. Maintaining Professional Competence: Approaches to Career Enhancement, Vitality, and Success Throughout a Work Life. San Francisco: Jossey-Bass Publishers, 1990.

Παραπομπή σε μορφή MLA (9th εκδ.)

Willis, Sherry L. Maintaining Professional Competence: Approaches to Career Enhancement, Vitality, and Success Throughout a Work Life. Jossey-Bass Publishers, 1990.