TY  - JOUR
A1  - Ellgring, Johann Heinrich
T1  - Comment to J. Rojahn: "Validity and reliability of data from naturalistic observational studies - problems and alternatives"
N2  - No abstract available
Y1  - 1978
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/3736
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-42520
ER  -