S. Vandermerwe and J. Rada, Servitization of business: Adding value by adding services, European Management Journal, vol.6, issue.4, pp.314-324, 1988.
DOI : 10.1016/0263-2373(88)90033-3

R. Wise and P. Baumgartner, Go downstream, Harvard Business Review, vol.77, issue.5, pp.133-141, 1999.

B. Resta, Designing and Configuring the Value Creation Network for Servitization, Italy, vol.66, issue.5, 2012.
DOI : 10.1007/978-3-319-32689-4_35

V. Mathieu, Service strategies within the manufacturing sector: benefits, costs and partnership, International Journal of Service Industry Management, vol.12, issue.5, pp.451-475, 2001.
DOI : 10.1108/EUM0000000006093

R. Oliva and R. Kallenberg, Managing the transition from products to services, International Journal of Service Industry Management, vol.14, issue.2, pp.160-172, 2003.
DOI : 10.1108/09564230310474138

A. Tukker, Eight types of product???service system: eight ways to sustainability? Experiences from SusProNet, Business Strategy and the Environment, vol.13, issue.4, pp.246-260, 2004.
DOI : 10.1002/bse.414

H. Gebauer, R. Krempl, E. Fleisch, and T. Friedli, Innovation of product-related services. Managing service quality, pp.387-404, 2008.

M. A. Cohen, N. Agrawal, and V. Agrawal, Winning in the Aftermarket, Harvard Business Review, vol.84, issue.5, pp.129-138, 2006.

H. Gebauer, E. Fleisch, and T. Friedli, Overcoming the Service Paradox in Manufacturing Companies, European Management Journal, vol.23, issue.1, pp.14-26, 2005.
DOI : 10.1016/j.emj.2004.12.006

H. J. Bullinger, K. P. Fähnrich, and T. Meiren, Service engineering???methodical development of new service products, International Journal of Production Economics, vol.85, issue.3, pp.275-287, 2003.
DOI : 10.1016/S0925-5273(03)00116-6

P. Coughlan and D. Coghlan, Action research for operations management, International Journal of Operations & Production Management, vol.22, issue.2, 2009.
DOI : 10.1108/01443570210417515

P. Reason and H. Bradbury, Handbook of Action Research, 2006.

D. Dayananda, R. Irons, S. Harrison, J. Herbohn, and P. Rowland, Capital budgeting: financial appraisal of investment projects, 2002.
DOI : 10.1017/CBO9780511753701

R. G. Cooper, S. J. Edgett, and E. J. Kleinschmidt, Portfolio management for new products, Perseus, 2001.

G. I. Kendall and S. C. Rollins, Advanced project portfolio management and the PMO: multiplying ROI at warp speed, J, 2003.

N. P. Archer and F. Ghasemzadeh, An integrated framework for project portfolio selection, International Journal of Project Management, vol.17, issue.4, pp.207-216, 1999.
DOI : 10.1016/S0263-7863(98)00032-5

URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=

D. N. Bridges, Project portfolio management: ideas and practices Project portfolio management. Selecting and prioritizing projects for competitive advantage, 1999.

B. Nelson, B. Gill, and S. Spring, Building on the stage/gate: An enterprise-wide architecture for new product development, Proceedings of the 28 th Annual Project Management Institute Seminars & Symposium, 1997.

A. K. Sanwal, Optimizing corporate portfolio management: aligning investment proposals with organizational strategy, 2007.
DOI : 10.1002/9781119196860

J. Hanski, S. Kunttu, M. Räikkönen, and M. Reunanen, Development of knowledgeintensive product-service systems, Espoo, 2012.

M. Sawhney, S. Balasubramanian, and V. V. Krishnan, Creating growth with services, MIT Sloan Management Review, vol.45, issue.2, pp.34-44, 2003.

P. Gaiardelli, V. Martinez, and T. Turner, Toward a Product-Service Business Model Configuration, Proceedings of the 10 th Euram Conference, 2003.