TY  - RPRT
TI  - [About longitudinal studies in epidemiology].
AU  - Cristina Pérez Andrés
AU  - José María Martín Moreno
DO  - 10.1590/s1135-57272004000200001
UR  - https://pubmed.ncbi.nlm.nih.gov/15199792/
ID  - 15199792
ER  -