A. Bertolino, A. Fantechi, S. Gnesi, and G. Lami. Software Product Lines - Research Issues in Engineering and Management, chapter 11, Springer-Verlag, (2006)
A. Reuys, S. Reis, E. Kamsties, and K. Pohl. Erfurt, (2003)Proceedings of the PLEES’03 International Workshop on Product Line Engineering: The Early Steps: Planning, Modeling, and Managing.