Muilenburg, James. "Chapter Nine: Parallels Outside of the Two Ways." The Literary Relations of the Epistle of Barnabas and the Teaching of the Twelve Apostles. Marburg, 1929, 159-164.
Muilenburg concedes that Barnabas and the Didache do not have many parallel passages outside the Two Ways material, but he does survey some which strike him as important. He views these mostly as moralistic rather than theological statements since, in his opinion, theological statements lose their significance with changing times and conditions (Muilenburg 1929, 159).
In considering similarities of eschatological passages, again, Muilenburg considers it a forgone conclusion that the Didache borrowed its views and themes from Barnabas. He cites numerous conceptual parallels (Muilenburg 1929, 160). Muilenburg does consider whether the Didache may have drawn the concepts from the Old Testament. However, he rejects this idea in favor of a borrowing from Barnabas due to the relative similarity of other passages and the assumption that the Didache has borrowed from Barnabas elsewhere (Muilenburg 1929, 161-162). The more obscure statements are also occasionally expanded in Barnabas.