TY  - RPRT
TI  - Drug discrimination under concurrent variable-ratio variable-ratio schedules.
AU  - D E McMillan
AU  - W C Hardwick
AU  - Mi Li
PY  - 2002
DO  - 10.1901/jeab.2002.77-91
UR  - https://pubmed.ncbi.nlm.nih.gov/11831785/
ID  - 11831785
ER  -