TY  - RPRT
TI  - Addendum to article on 'visit-based sampling'.
AU  - D S Shepard
AU  - R Neutra
PY  - 1979
DO  - 10.2105/ajph.69.9.954
UR  - https://pubmed.ncbi.nlm.nih.gov/474853/
ID  - 474853
ER  -