TY  - RPRT
TI  - Preference and resistance to change in concurrent variable-interval schedules.
AU  - Matthew C Bell
AU  - Ben A Williams
PY  - 2002
DO  - 10.3758/bf03192907
UR  - https://pubmed.ncbi.nlm.nih.gov/12017966/
ID  - 12017966
ER  -