Or Luther's small Catechism for that matter.
Or for that matter, On the Incarnation by St. Athanasius, the epistles of St. Ignatius of Antioch, Against Heresies by St. Irenaeus of Lyons, the Apologies of St. Justin Martyr, the Orations of St. Gregory the Theologian, 1 Clement (not an apocrypha, by the way, but a Patristic writing from the first century), the Didache, the Apostolic Tradition of Hippolytus, the Mystagogical Catecheses of St. Cyril of Jerusalem, the writings of St. Basil and his brother St. Gregory of Nyssa (who along with St. Gregory the Theologian were the three most important of the Cappadocians), the homilies of St. John Chrysostom, the Hymns on Paradise and other hymns and metrical homilies by St. Ephraim the Syrian, and that’s only in the first four centuries of the church, before the dreadful Nestorian schism about 400 years after the death of Christ.
Contrary to the beliefs of some Restorationist denominations, the Nestorian schism is the only schism where one could argue that it remains in effect today, in that it is the root cause of the lack of complete unity between the three Eastern communions (in alphabetical order, the Church of the East, the Eastern Orthodox and the Oriental Orthodox). Indeed most Restorationists do not even acknowledge the existence of the Eastern churches, instead viewing everything through a false dichotomy, for example, the Adventist or Landmark Baptist idea that various historical groups, which we know from their own writings had virtually nothing in common with either denomination, for example, the Waldensians, or the Bogomils, or the Albigensians, or various ancient sects such as the Montanists, Paulicians and so on, all of which, aside from the Waldensians, embraced strange doctrines, as being some kind of remnant versus an apostate Roman Catholic Church which supposedly controlled everything else. This is demonstrably false, as a matter of fact.
When 19th century works supersede those of the Early Church Fathers, this is a problem, because it disconnects us from the historic interpretation of the Bible that was agreed upon everywhere, by everyone, to varying extents, at least until the Radical Reformation in the mid 16th century, which Martin Luther was horrified by, but in many cases have beliefs which appear to have originated in the 19th century.