TY  - RPRT
TI  - Contingency management: schedule effects.
AU  - John M Roll
AU  - Steve Shoptaw
PY  - 2006
DO  - 10.1016/j.psychres.2005.12.003
UR  - https://pubmed.ncbi.nlm.nih.gov/16905197/
ID  - 16905197
ER  -