Validity (method.) ; Evaluation criterion (method.) ; Ethik (Forschung) ; Ethics (in research) ; Research ethics ; Tonband (method.) ; Audiotape (method.) ; Videokassette (method.) ; Video tape (method.) ; Audio-visual aids (method.) ; Family communication ; Psychotherapy ; English (British) ; Grossbritannien (engl. Sprache in) ; Great Britain (English language in) ; Englisch in Grossbritannien; English in Great Britain; British English
