Müller, Jörg M. ; Achtergarde, Sandra ; Winkel, Sandra ; Frantzmann, Hanna ; Steinberger, Kathrin ; Skorozhenia, Olena ; Beyer, Thomas ; Fürniss, Tilman ; Furniss, Tilman ; Furniss, Tilman ; Furniss, Tilman ; Postert, Christian: Inter-rater reliability and aspects of validity of the parent-infant relationship global assessment scale (PIR-GAS)