In the wake of World War II, economics has undergone a transformation from a literary oriented discipline towards a scientific one. One central vehicle of this changing culture has been the use of mathematical proof techniques specifically in general equilibrium theory. This impersonal mode of expression provided a new meta-theoretical framework to the discipline but, as we show in this contribution, simultaneously affected the reward system of the discipline. We thus historicize the post-1945 transformation of economics by describing the effects it had on the role of scientific credit - issues that range from (co)authorship, refereeing process, supervision of students, down to scientific prizes such as the Nobel Prize. One self-reflective element of this discussion is to consider the historical accounts of the scientists as inherent to the negotiation of credit, and, concomitantly, the writing of the history of science as one layer of the changing reward system in a regime of impersonal knowledge. The exemplary case we consider is the existence proof in general equilibrium theory presented by Lionel McKenzie, and in a joint paper by Kenneth Arrow, and Gerard Debreu. The latter two have each received a Nobel Prize in 1972, and 1983 respectively, while the former remained less known to the broader community of economists.