premise: IX. The CONTRACTOR will return all documents, information, knowledge, samples and data provided in the course of the cooperation including all copies thereof to the PURCHASER.  In the case of retention of documents, information, knowledge, samples and data or copies by the CONTRACTOR or his assistants or agents, the PURCHASER may assert claim for damages. X. The CONTRACTOR will observe the BDSG (Bundesdatenschutzgesetz = German Data Protection Act), regulations and other regulations for the data protection.  In the case that the CONTRACTOR is granted access no matter of which kind by the PURCHASER to data for performance of the contractual works in terms of the BDSG or made known such data by the PURCHASER, the CONTRACTOR will only consign Employees, Assistants or Agents with the performance of the contractual work, who are obliged to data secrecy in terms of § 5 BDSG.  On request of the PURCHASER, the CONTRACTOR will present the agreement made with the Employees, Assistants or Agents. The CONTRACTOR will not make available or known the data forwarded or made known by the PURCHASER in terms of the BDSG to third parties, neither directly nor indirectly, and only use it to perform the work. After completion of the work, the CONTRACTOR will return all data forwarded by the PURCHASER including the copies thereof to the PURCHASER or completely delete the data including the copies thereof.