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\bibitem{Nolting_etal2001} Nolting, H. - D., Follmann, A., Alfert, A., \& Berger, J. (2001). \textit{Handbuch zur Qualit{\"a}tssicherung in der ambulanten Substitutionstherapie Opiatabh{\"a}ngiger : ASTO-Handbuch}. M{\"u}nster: {\"A}rztekammer Westfalen-Lippe.

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