TY  - RPRT
TI  - Programmed self-instruction in oral hygiene.
AU  - D Bratthall
PY  - 1967
DO  - 10.1111/j.1600-0765.1967.tb01891.x
UR  - https://pubmed.ncbi.nlm.nih.gov/4237479/
ID  - 4237479
ER  -