TY  - RPRT
TI  - Validity and reliability--What's it all about? Part 1. Validity in quantitative studies.
AU  - Alison Twycross
AU  - Linda Shields
PY  - 2004
DO  - 10.7748/paed2004.11.16.9.28.c954
UR  - https://pubmed.ncbi.nlm.nih.gov/15633276/
ID  - 15633276
ER  -