Frege, Russell, Ramsey and the notion of an arbitrary function
In Frege's Philosophy of Language, Dummett claims that Frege's notion of a function coincides with the notion of an arbitrary correspondence (, pp. 223 and 177).
Benis-Sinaceur, H. , Panza, M. , Sandu, P.-G. (2015). Frege, Russell, Ramsey and the notion of an arbitrary function, in Functions and generality of logic, Dordrecht, Springer, pp. 97-116.
This document is unfortunately not available for download at the moment.