In his 1985 article on the sources of Luke’s passion narrative, for example, Matera says, “I am arguing that Luke did not have another continuous [passion narrative] in addition to Mark. It is clear that at times he may have drawn from individual traditions not known to Mark. But when he does so, he integrates them into Mark’s narrative.” See his “The Death of Jesus according to Luke: A Question of Sources,” CBQ 47 (1985): 472. I cannot find what sources he is using because I do not have access to the article in my personal library and seminary library.