ASKING THE IMPORTANT QUESTIONS: What is the Oldest Manuscript of the New Testament? (Dirk Jongkind, ETC).
More on recent developments regarding P52 here.
Also, possibly related, Dorothy Lobel King asks: Is this More of the "First Century" Gospel of Mark? I haven't been following this story very carefully, but I have some background here and here and links. I am not a Greek epigrapher and I have no view about any possible relationship of these fragments to one another.