A. W. Ward & A. R. Waller, eds., Cambridge History of English and American Literature, Vol. VII, Section V (Milton), subsection 20 ("His Latin writings"). New York: G.P. Putnam's Sons; Cambridge, England: University Press, 1907–21. As given at Bartleby.com.
For examples of Milton's writings at this time being termed propaganda, see the "Life of John Milton" at luminarium.org ("For his propaganda writings, Milton had to go into hiding, for fear of retribution from the followers of King Charles II"); and R. Page Arnot's 1921 review of Leon Trotsky's Terrorism and Communism at marxists.org (where Arnot says "Trotsky achieves a miracle of compression and propaganda....For any parallel we have to go back to John Milton's 'Defensio pro Populo Anglicano'").
marxists.org
For examples of Milton's writings at this time being termed propaganda, see the "Life of John Milton" at luminarium.org ("For his propaganda writings, Milton had to go into hiding, for fear of retribution from the followers of King Charles II"); and R. Page Arnot's 1921 review of Leon Trotsky's Terrorism and Communism at marxists.org (where Arnot says "Trotsky achieves a miracle of compression and propaganda....For any parallel we have to go back to John Milton's 'Defensio pro Populo Anglicano'").
michaelbryson.net
Michael Bryson, "Background for the Defense of the English People," located here.