8903
As a young Congressman , Rumsfeld attended seminars at the University of Chicago , an experience he credits with introducing him to the idea of an all volunteer military , and to the economist Milton Friedman and the Chicago School of Economics .
 person: Rumsfeld; organization: University of Chicago; person: Milton Friedman; organization: Chicago School of Economics
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: Rumsfeld; organization: University of Chicago; person: Milton Friedman; organization: Chicago School of Economics