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Most roller derby leagues adopt the rules and guidelines set by the Women 's Flat Track Derby Association or its open gender counterpart , Men 's Roller Derby Association , but there are leagues that play on a banked track , as the sport was originally played from the 1930 s .
 Women 's Flat Track Derby Association, Men 's Roller Derby Association
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Women 's Flat Track Derby Association, Men 's Roller Derby Association