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The later work , in the 3rd century BC , of Archimedes and Apollonius studied more systematically problems on conic sections , and also involved the use of coordinates .
 person: Archimedes; person: Apollonius
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: Archimedes; person: Apollonius