Who are the authors of the two books which begin with z in the new testament?

The two books in the New Testament that begin with the letter "Z" are the Book of Zephaniah and the Book of Zechariah. However, Zephaniah is actually part of the Old Testament, while the relevant book in the New Testament is the Book of Revelation, traditionally attributed to John. Therefore, the only book in the New Testament that starts with "Z" is Zechariah, which is not a New Testament book; thus, there are no books starting with "Z" in the New Testament.