TY  - RPRT
TI  - Executive summary? All about validating scales and stages.
AU  - Isolde den Tonkelaar
AU  - Frank J Broekmans
AU  - Evelien J de Boer
AU  - Egbert R te Velde
PY  - 2002
DO  - 10.1016/s0015-0282(02)04220-6
UR  - https://pubmed.ncbi.nlm.nih.gov/12414009/
ID  - 12414009
ER  -