43132
He was the Official Secretary to the Governor-General of Australia between 1973 and 1990 , in which capacity he served Sir Paul Hasluck , Sir John Kerr , Sir Zelman Cowen , Sir Ninian Stephen and Bill Hayden .
 Australia, Paul Hasluck, John Kerr, Zelman Cowen, Ninian Stephen, Bill Hayden
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Australia, Paul Hasluck, John Kerr, Zelman Cowen, Ninian Stephen, Bill Hayden