“…Other implementation studies focus on reviewing and informing policy [13,16,17,[53][54][55][56][57][58][59][60][61][62][63][64][65][66][67], specifically on product design for the CE [8,9,14,[64][65][66] as well as assessments of firms' [67,68], consumers' [69][70][71], and officials' [72] awareness of and attitudes towards the CE's concepts and its components. Two contributions are concerned with business model research [73,74]. More abstract studies seek to define the CE more clearly and assess its future challenges [75][76][77][78] or highlight the social [2,15,79,80] or economic aspects of the concept further [1,18].…”