Schilpp, Paul Arthur
Wilhelm Risse
James William Bernauer
Abraham Fraenkel
Havelock Ellis
E. M. Barth
Πλάτων
Carl Mitcham
Plotinus
Joan Nordquist
Manly Palmer Hall
Jan Yoors
Guido Frongia
Pitirim Aleksandrovich Sorokin
Wilhelm Totok
Unknown Author
Ferdinand van der Haeghen
Gustav Radbruch
Karl H. Potter
Rolando M. Gripaldo