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Killing Royal Ulster Constabulary officers and assassination of unionist politicians was one of a number of methods used in the Provisional IRA campaign 1969 – 1997 .
 Royal Ulster Constabulary, Provisional IRA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Royal Ulster Constabulary, Provisional IRA