321918
From 1972 through 1979 , he rode on the Australian racing circuit , racing against Gregg Hansford , Warren Willing , Kenny Blake and Harry Hinton .
 Gregg Hansford, Harry Hinton
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Gregg Hansford, Harry Hinton