TY  - RPRT
TI  - Rates and patterns of responding with concurrent fixed-interval and variable-interval reinforcement.
AU  - J A Nevin
PY  - 1971
DO  - 10.1901/jeab.1971.16-241
UR  - https://pubmed.ncbi.nlm.nih.gov/16811545/
ID  - 16811545
ER  -