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. .