@inproceedings{SteinbergWoll2013, author = {Falk Steinberg and Ralf Woll}, title = {Approaches for Handling of difficult to quantify Characteristics in Product Development}, booktitle = {Proceedings of the 15th QMOD Conference on Quality and Service Sciences, Poznan (Poland) 2012}, pages = {1746 -- 1763}, year = {2013}, }