Wilhelm Bousset, in "Kyrios Christianity," page 295, says, "The testimony for the wide distribution of the simple baptismal formula [in the Name of Jesus] down into the second century is so overwhelming that even in Matthew 28:19, the Trinitarian formula was later inserted."
"Akaebe maka nkesa sara mbara nke usoro baptizim dị mfe [n'aha Jizọs] ruo narị afọ nke abụọ karịrị akarị nke na ọbụna na Matiu 28:19, e mechara tinye usoro Atọ n'Ime Otu."