Excerpt from Peter of Spain: A brief passage from the Treatise on Distributions, in Joseph Mullally's translation. Discusses the problem of whether the negation of a statement makes it universal or renders it indeterminate.
Excerpts from the Commentary on Peter of Spain's Tractatus: Selections from this secondary work by Simon of Faversham, translated by John Longeway.
Peter of Spain (Petrus Hispanus): Life and work of 13th century logician and author of the Tractatus; from the Stanford Encyclopedia by Joke Spruyt.