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Later , like his fellow students , he studied with Gerrit Dou , his father 's brother-in-law , until 1659 , when he started on his Grand Tour .
 person: Gerrit Dou
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: Gerrit Dou 
Answer:
 person: Gerrit Dou