It has been almost 4 years since I published my book-length work refuting Sola Scriptura, the formal doctrine of Protestantism:
Not By Scripture Alone: A Latter-day Saint Refutation of Sola Scriptura
Although many Protestant apologists have been challenged to refute this, including some of the more "big name" anti-Mormons out there, there has been no meaningful attempt to respond (not surprising, as Sola Scriptura is a nonsensical doctrine easily refuted by historical-grammatical exegesis). Indeed, the attempt responses that have been provided have been, so far, jokes (and that is me trying to be nice), including from one Reformed apologist I am convinced has a learning disability.
Here are my responses to these attempts:
Jeremiah Boddy
Response to an attempted Rebuttal of "Not By Scripture Alone"
Dealing with the Issue of Sola Scriptura
Kathy Petersen