MacTutor History of Mathematics: Arnauld, Antoine  
   Biographical article by J.J. O'Connor and E.F. Robertson. Emphasizes Arnauld's Jansenism.
   http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Arnauld.html

Arnauld  
   Article from the 1912 Catholic Encyclopedia on the Arnauld family, with a lengthy section on Antoine Arnauld.
   http://www.newadvent.org/cathen/01742a.htm

Wikipedia: Antoine Arnauld  
   Article from this openly-edited reference work, based on that in the 1911 Encyclopaedia Britannica.
   http://www.wikipedia.org/wiki/Antoine_Arnauld

Correspondence Relating to the Metaphysics  
   Letters exchanged among Leibniz, Arnauld and Hessen-Rheinfels. A revised version of the 1902 George R. Montgomery translation.
   http://www.class.uidaho.edu/mickelsen/texts/Leibniz%20-%20Correspondence.htm

Antoine Arnauld (1612-1694)  
   An article placing Arnauld in intellectual context, with a timeline of his life and selected bibliography.
   http://oregonstate.edu/instruct/phl302/philosophers/arnauld.html

Biography.com: Arnauld, Antoine  
   Very brief article on the philosopher and religious thinker.
   http://search.biography.com/print_record.pl?id=3943

Arnauld Texts  
   George MacDonald Ross's translation of a section "on Method" from the Port Royal Logic, anonymously authored by Antoine Arnauld and Pierre Nicole. With prefatory material.
   http://www.philosophy.leeds.ac.uk/GMR/hmp/texts/modern/arnauld/arnindex.html

FOLDOC: Arnauld Antoine  
   Brief article from this philosophical database, with links to related topics.
   http://www.swif.uniba.it/lei/foldop/foldoc.cgi?Arnauld+Antoine