Textual Criticism and Synoptics, the Case of ευθυς

On the importance of textual criticism in synoptic studies: the case of ευθυς. I have always viewed ευθυς as a nice marker of Matthew's use of Mark. [For the record, I am confident that both were composed in Greek. What of the Hebrew tradition in Papias? I see the Hebrew Matthew of Papias as refering [...]