TY  - RPRT
TI  - Programmed instruction, teacher ability, and subject matter difficulty.
AU  - J J La Gaipa
PY  - 1968
DO  - 10.1080/00223980.1968.10543431
UR  - https://pubmed.ncbi.nlm.nih.gov/5641705/
ID  - 5641705
ER  -