How real was the threat or prospect of socialism in italy in the years 1919-21

List of arguments for and against on how real was threat/prospect of Socialism in Italy during Biennio Rosso (1919-21) including statistic information; no historiography

Sources:

Mark Robson, Italy: The Rise of Fascism 1915-45, 2008

John Hite, Chris Hinton, Fascist Italy, 2008