This chapter proposes understanding references as a particular valuation device through which creative worth is assessed and mobilized in advertising processes. It draws a comparison with the use of references in laboratory work by comparing the work of referencing in advertising studios with the role of references in scientific work, as captured by Latour's concept of circulating reference. The chapter presents an overview of the necessity for references in ordinary creative work. It describes the practice of referencing for advertising campaigns, focusing on the activity of collecting and ordering. The chapter takes a different standpoint to unpack creative work in advertising agencies. Creative work in an advertising agency is often described by advertisers as related to a series of team meetings where potential creative solutions for a campaign are presented, discussed and reshaped. The chapter describes the process of synthesis, the generative moment that comes from the use of different references as a key moment of creative work.