Rogers, Carl (1957). "The necessary and sufficient of therapeutic personality change". Journal of Consulting Psychology. 21 (2): 95–103. doi:10.1037/h0045357. PMID13416422.
Wilkins, P (2000). "Unconditional positive regard reconsidered". British Journal of Guidance & Counseling. 28 (1): 23–36. doi:10.1080/030698800109592.
Rogers, Carl (1957). "The necessary and sufficient of therapeutic personality change". Journal of Consulting Psychology. 21 (2): 95–103. doi:10.1037/h0045357. PMID13416422.