Appel, Karol (1857–1930)
Buisson, Ferdinand (1841–1932) Renard, Georges Francis (1847–1930) Séailles, Gabriel (1852–1923)
Kautsky, Karl (1854–1938)
Lafargue, Paul (1842–1911)
Perl, Feliks (1871–1927)
Dybowski, Benedykt (1833–1930)
Garfein-Garski, Stanisław (1867–1928)
Biegański, Władysław (1857–1917)
Greulich, Hermann (1842–1925)