Joel Marcus, “The Gospel of Peter as a Jewish Christian document” NTS 64 (2018), 473-494, is a somewhat speculative article on Evangelium Petri. It is noted here because Marcus returns to the Didascalia, having previously discussed this document in his “The Testaments of the Twelve Patriarchs and the Didascalia Apostolorum: a common Jewish Christian milieu?” JTS 61 (2010), 596–626. Here he turns to the Quartodeciman background of the Vorlage to chapter 21 (Syriac), noting here the nexus of relationship between it, Evangelium Petri, and other Quartodeciman literature, and the complex relationship between Quartodeciman Christianity and the Jewish matrix of its genesis.

As already said, the conclusion is somewhat speculative, but is not impossible, and the piece is worth reading.