Text and Canon

I have an interview at Tyndale House tomorrow regarding issues of "text and canon." I've found it difficult to read older authors discussing canon issues, because their terminology seems to be different from mine (and I think others). Zahn believed the NT was canonical by the end of the first century because it was used in the worship and church fathers quoted it; Harnack believed the NT was canonical by the end of the second century because church fathers were now using the quotation formula: "it is written" (gegraptai); Sundberg aptly distinguished between Scripture and canon by describing Scripture as the authoritative text of a community while canon was an exclusive list of these texts. Therefore, he considers the NT canonical in the 4th century, based on Athanasius' Easter letter, the Muratorian canon, and the councils.