“…The search architecture was obtained from two snowball sampling analyses (SBAs), i.e., a study of "references to references" (Wohlin, 2014), of previous academic publications discussing integration of sustainability into product development and requirements. The first SBA started in Jaghbeer et al (2017), leading towards authors such as (Byggeth and Hochschorner, 2006;Bovea and Pérez-Belis, 2012;Inoue et al, 2012;Gaziulusoy et al, 2013;Hallstedt et al, 2013;Schöggl et al, 2016;Zetterlund et al, 2016;Hallstedt, 2017). A research map that visualised the referencing between these articles led towards (Hallstedt et al, 2013), which was chosen as a reference point for a second SBA.…”