Testimonianze
- Rossanda (2005c)
- Valera (1882)
- Pasolini (1941)
- Carducci (1864)
- Cecchi-Praz (1923)
- Ciccotti (1908)
- Alicata (1943)
- Papini (1913b)
- Labriola (1881-1887)
- Romano (1979d)
- Ginzburg - Prosperi (1975)
- Croce (1927)
- Vichi (1953)
- Calvino (1979b)
- Ginzburg, Carlo (2001)
- Serao (1885)
- Huetter (1963)
- Fornari (1874)
- Guccini-Macchiavelli (1998)
- Calamandrei (1944)
- Ginzburg, Carlo (1995)
- Pasquali (1929a)
- Calasso (2021)
- Russo (1958)
- Manzini (1944)
- Petrucci (1995)
- Marchesi (1940)