|Geach, Peter T.
Books on Amazon
Variable/Description/Proxy/GeachVsCarnap: in his rules for descriptions E.g. "" ____ (ix) (.. x ..) ____ "etc. the strokes do not act, as Carnap believes as vacancies (proxy) but as variables - Carnap thinks, if he renames them, he could prevent his problems with variables.
"stand for"/Geach: no difference whether I say, a predicate "stands for" a proposition or was its name - ((s) as a proxy name?).
Logic Matters Oxford 1972