Eusebius, Ecclesiastical History, Book 3, Chapter 39. Quotes Irenaeus, then Papias himself, and comments on the relationship of Papias to 'John.' With notes. 123K.
Thorough essay on what we know of this bishop, called by St. Irenaeus 'a hearer of John.' Also an exposition of the writings of Papias, who died around 120.
Five-page article by Benjamin W. Bacon, with contributions from others, dwells on the thorny question of Papias's relation to John. Includes bibliography. Requires ability to view PNG files.