Bartoszewski, Jankowski, and Kwapisz address the problem of convergence of some iterative methods for general differential-algebraic systems. The techniques involved are constructive and simple. Two examples are provided to illustrate the convergence rates. The results are interesting, and will be useful to academic researchers.

There are many papers devoted to the study of differential-algebraic systems. The authors have restricted their attention to the references that are close to their interest. However, the paper by E.J. Dean et al. [1] would have been a very good addition to their bibliography. This paper clearly explains the idea of the operator splitting approach, used by the authors without motivation (page 346). Overall, the paper is well written, and is a nice contribution to the study of differential-algebraic systems.