TY  - RPRT
TI  - Matching to reinforcer value: human concurrent variable-interval performance.
AU  - M J Cliffe
AU  - S J Parry
PY  - 1980
DO  - 10.1080/14640748008401845
UR  - https://pubmed.ncbi.nlm.nih.gov/7443972/
ID  - 7443972
ER  -