RT Article T1 Biological and psychological aspects of depression JF Behavior therapy VO 22 IS 2 SP 201 OP 228 A2 Shelton, R. C. A2 Hollon, S. D. A2 Purdon, S. E. A2 Loosen, P. T. LA English YR 1991 UL https://krimdok.uni-tuebingen.de/Record/164015275X K1 Depression