TY  - RPRT
TI  - Two-key concurrent paced variable-interval paced variable-interval schedules of reinforcement.
AU  - M Moffitt
AU  - C P Shimp
PY  - 1971
DO  - 10.1901/jeab.1971.16-39
UR  - https://pubmed.ncbi.nlm.nih.gov/16811533/
ID  - 16811533
ER  -