Catholic Encyclopedia: St. Felix of Nola: Third-century confessor. Feast day 14 January. Possibly the same as St. Felix of Nola, bishop and martyr.
Catholic Online: St. Felix of Nola: Short biography.
For All the Saints: Felix of Nola: Biographical portrait, says he died in 260.
Patron Saints Index: Felix of Nola: Profile says that he was martyred c. 250.