http://ia331320.us.archive.org/1/items/secrethistoryofp00croxuoft/
http://ia310126.us.archive.org/1/items/ancientphilosoph00epicuoft/
http://ia360616.us.archive.org/2/items/journeystolittle00hubbrich/
http://ia360928.us.archive.org/2/items/wisemenofgreecei00blacrich/
http://ia350642.us.archive.org/1/items/bygonebeliefsbei00redguoft/
http://ia350628.us.archive.org/2/items/platoorprotagora00schirich/