Which scholars, historical figures, or churches have argued that the synoptic gospels (Matthew, Mark, and Luke) were all written independently without access to any of the other gospels? What arguments have they used?
This question isn't about particular theories of dependence (Augustinian, Ferrer, Griesbach, two sources, etc.), but rather about people denying literary dependence entirely.
(This question comes from the comments here, but I figured it'd be better to have is as a separate question.)