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In 1967-68 he compiled , with Neil Slaven , the groundbreaking discography Blues Records 1943-1966 , and through a great many articles and discographical research led the way in documenting the careers and recordings of hitherto under-recognised blues musicians .
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Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities:  
Answer:
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