On a central limit theorem in renewal theory

Serfozo (2009, Theorem 2.65) gives a useful central limit theorem for processes with regenerative increments. Unfortunately, there is a gap in the proof. We fill this gap, and at the same time we weaken the assumptions. Furthermore, we give conditions for moment convergence in this setting. We give also further results complementing results in Serfozo (2009) on the law of large numbers and estimates for the mean; in particular, we show that there is a gap between conditions for the weak and strong laws of large numbers.