"Geys's archival practice is evident not only in his gigantic photo archive but also in his inventory of all the works he has created since his debut in 1958. The inventory, arranged chronologically, lists the following information for each work: “subject” (the title of the work), “nature” (the material(s), plus sometimes the dimensions of the work), “year,” and “number” (the number of copies, varying from 1 to “unlimited”)."

Liesbeth Decan, Conceptual, Surrealist, Pictorial: Photo-based Art in Belgium (1960s – early 1990s), Leuven University Press, 2016, p. 65