Gaya APA

Sperry, L., , . (2010). Core competencies in counseling and psychotherapy: becoming a highly competent and effective therapist . London: London: Routledge, 2010.

Gaya MLA

Sperry, Len., , . "Core competencies in counseling and psychotherapy: becoming a highly competent and effective therapist". London: London: Routledge, 2010, 2010. .