In Not By Scripture Alone: A Latter-day Saint Refutation of Sola Scriptura, one of the
books against Sola Scriptura I recommended at the end was that of George Agius,
Tradition and the Church. While it has been reprinted by TAN Books (which I
own), it is still a hard-to-find volume. Fortunately, it has now been put on
Archive.org:
While Agius was often a little too over-enthusiastic to interpret
early Christian writings as if they were supportive of later Catholic dogma, it
is a useful book as it shows (1) early Christians did not hold to the formal
sufficiency of the Bible and (2) it is a good work for understanding how
Catholics approach “Tradition.”