Muratorian fragmenta list of the New Testament writings, apparently drawn up by a contemporary of Irenæus, about 170 A.D., edited by Muratori. It counts four Gospels, Acts, thirteen Pauline epistles (excluding Hebrews), 1 John, then Jude; 2 and 3 John are reckoned among catholic epistles. The Apocalypse is included
The first evidence regarding it is found in the Muratorian fragment and in Irenaeus and Tertullian.
"History of Dogma, Volume 2 (of 7)" by Adolph Harnack