TY  - RPRT
TI  - The Chief Scientist reports.... Problems in mounting and maintaining longitudinal studies--examples from dental health services research.
AU  - J A Davies
AU  - H E Fyffe
AU  - N B Pitts
PY  - 1992
UR  - https://pubmed.ncbi.nlm.nih.gov/1517092/
ID  - 1517092
ER  -