@incollection{HartoghWickel2004, author = {Theo Hartogh and Hans Hermann Wickel}, title = {Zur musikalischen Professionalit{\"a}t in der Sozialen Arbeit}, booktitle = {Th. Hartogh \& H. H. Wickel, Handbuch: Musik in der Sozialen Arbeit}, edition = {1.}, isbn = {3-7799-0787-9}, year = {2004}, }