TY  - RPRT
TI  - [Methodology in discriptive gerontologic studies--basic problems of the so-called cross sectional and longitudinal studies].
AU  - D Voigt
AU  - G Brüschke
PY  - 1969
UR  - https://pubmed.ncbi.nlm.nih.gov/5380258/
ID  - 5380258
ER  -