Walborn, F. S. (1996). Process variables: Four common elements of counselling and psychotherapy. Brooks/Colege Pub.
Chicago-viite (17. p.)Walborn, Frederick S. Process Variables: Four Common Elements of Counselling and Psychotherapy. Pacific Grove, Calif: Brooks/Colege Pub, 1996.
MLA-viite (9. p.)Walborn, Frederick S. Process Variables: Four Common Elements of Counselling and Psychotherapy. Brooks/Colege Pub, 1996.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.