Analysis of information sources in references of the Wikipedia article "Synoptic Gospels" in English language version.
Hennell, in his 'Origin of Christianity,' says that:- 'Some one after Matthew wrote the Greek Gospel which has come down to us, incorporating part of the Hebrew one, whence it was called the Gospel according to Matthew, and, in the second century, came to be considered as the work of the Apostle.'
The literary history of the Gospels will turn out to be a simpler matter than we had supposed. St. Matthew will be seen to be an amplified version of St. Mark, based on a decade of habitual preaching, and incorporating oral material, but presupposing no other literary source beside St. Mark himself. St. Luke, in turn, will be found to presuppose St. Matthew and St. Mark, and St. John to presuppose the three others. The whole literary history of the canonical Gospel tradition will be found to be contained in the fourfold canon itself, except in so far as it lies in the Old Testament, the Pseudepigrapha, and the other New Testament writings. [...] Once rid of Q, we are rid of a progeny of nameless chimaeras, and free to let St. Matthew write as he is moved.
