I have written a few books that provides all the evidence, but in a nutshell, follow the trail for naming of Matthew, Mark, and Luke and you come up empty with missing documentation, words of people who came many years after the gospels were written, and no valid evidence. James, Peter and John and even Andrew were eyewitnesses selected by Jesus to see and hear everything he did and said. If the Gospels are eyewitness accounts then the words in them had to come from these men. My analysis of scripture proved that there are three different eyewitness versions.
Nicodemus as the author of Matthew makes sense because the work is clearly from a religious leader who had access to many things only a religious leader could have witnessed. These men as the authors also provide an explanation for the copying aspect of the gospels. Nicodemus, James, John and Peter through Silas as authors prove the story of Jesus as true and that made me a 100% believer and follower of Christ. Matthew, Mark, and Luke as authors leave the Gospels without any proof of validity besides the words of other men who lived years after the gospels were written (Papias, Irenaeus, Eusebius, etc.).