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He also simplified travel in Brandenburg and the Duchy of Prussia by connecting riverways with canals , a system that was expanded by later Prussian architects , such as Georg Steenke ; the system is still in use today .
 Brandenburg, Duchy of Prussia, Georg Steenke
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Brandenburg, Duchy of Prussia, Georg Steenke