1. Wiegers KE (1999) First things first: prioritizing requirements 1, no. September, pp 1–6
2. Song W (2017) Computers in industry requirement management for product-service systems: Status review and future trends. Comput Ind 85:11–22
3. Berkovich M, Esch S, Leimeister JM, Krcmar H (2009) Requirements engineering for hybrid products as bundles of hardware, software and service elements—a literature review product as bundles of hardware, software and service elements—a literature review
4. Müller P, Schulz F, Stark R (2010) Guideline to elicit requirements on industrial product-service systems. In: Proceedings of the 2nd CIRP IPS2 conference, pp 109–116
5. Berkovich M, Marco J, Hoffmann A, Krcmar H (2014) A requirements data model for product service systems, pp 161–186