Jefferson and/or Mussolini. Fascism as I Have Seen It.
Published in 1935, Jefferson and/or Mussolini underlies Eleven New Cantos. It gives collateral information, includes indications about Pound's reading of the sources and contains the ideological program that gives structure and meaning to the composition of this section of the poem.
The pamphlet is available online at Internet Archive.
The pdf is available on The Cantos Project/ General Sources. Please find it here.