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However , the issue was renewed last week when researchers from Ruhr - University Bochum in Germany published a paper on different attacks against network printers and an assessment of 20 printer models .
 researchers: discoverer; printer models: vulnerable system; last week: time; network printers: vulnerable system; Ruhr - University Bochum: discoverer
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: discover vulnerability 
  Option: vulnerable system owner, vulnerability, capabilities, time, vulnerable system version, discoverer, common vulnerabilities and exposures, supported platform, vulnerable system 
Text: {0} 
Answer:
 researchers: discoverer; printer models: vulnerable system; last week: time; network printers: vulnerable system; Ruhr - University Bochum: discoverer