TY  - RPRT
TI  - Two-step PPD testing for nursing home patients.
AU  - E Lefton
PY  - 1989
DO  - 10.1111/j.1532-5415.1989.tb01264.x
UR  - https://pubmed.ncbi.nlm.nih.gov/2738288/
ID  - 2738288
ER  -