Roberta Mazza (2019). Dating Early Christian Papyri: Old and New Methods – Introduction, in Journal for the Study of the New Testament, vol. 42(1) (2019) [1]
See the Leuven Database of Ancient Books, P. Ryl. 470. About the date of the papyrus Rylands III 470, see also Hans Förster, «Die älteste marianische Antiphon - eine Fehldatierung? Überlegungen zum "ältesten Beleg" des Sub tuum praesidium», in Journal of Coptic Studies 7 (2005), pp. 99-109.
The first Christian hymnal : the songs of the ancient Jerusalem church. Stephen J. Shoemaker. Provo, Utah. 2018. pp. xxviii. ISBN978-1-944394-68-4. OCLC1047578356.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)