Most Reformed apologists are presuppositionalists (for a book-length discussion of this methodology, see Greg Bahnsen's Van Til's Apologetic: Reading and Analysis [Presbyterian & Reformed, 1998]).
For some accessible online critiques of this flawed apologetic work (which is basically "baptised" circular reasoning and fideism), see:
For a good book-length critique of Cornelius Van Til and his apologetic methodology, see Classical Apologetics, eds. John H. Gerstner, Arthur W. Lindsley, and R.C. Sproul (Zondervan, 1984).
