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He performed on over 17,000 documented recording sessions , backing popular acts such as Elvis Presley and Roy Orbison .
 person: Elvis Presley; person: Roy Orbison
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Elvis Presley; person: Roy Orbison