Exploring Service Science 9th International Conference, IESS 2018, Karlsruhe, Germany, September 19-21, 2018 : proceedings - Satzger, Gerhard; Patrício, Lia ca. 20./21. Jh; Zaki, Mohamed; Kühl, Niklas; Hottum, Ralf (Lecture Notes in Business Information Processing, 2018)