Catholic Encyclopedia - Pope St. Sixtus I. Also spelled Xystus. Martyr, reigned for ten years in the very early part of the second century. www.newadvent.org/cathen/14031b.htm
For All the Saints - Short biography of Pope St. Sixtus I. users.erols.com/saintpat/ss/0403.htm#sixt
Popes Through the Ages - Profile of St. Sixtus I, from the book by Joseph Brusher. www.cfpeople.org/Books/Pope/POPEp7.htm
The Ecole Glossary - Brief article on Pope St. Sixtus I, by Karen Rae Keck. cedar.evansville.edu/~ecoleweb/glossary/sixtusi.html