"This paper" vs "That paper" in an abstract

Unlike many languages, most varieties of modern English have a two-way rather than a three-way system of demonstratives, exemplified by "this" and "that". "Yonder" exists for a third term, but is not much used in most varieties.

This means that words in the "that" class (including "those" and "there") do not have any particular association with the hearer: they are simply relatively remote from the speaker.

So, though the paper may be immediate for the reader, in English the reader does not figure in determining whether it is proximal or not for the writer, and so "this" is used. "That" would be likely to be misunderstood.

If the "this/that" describes the paper of which the abstract is a part (or which the abstract describes), then "this" should be used, since the paper is at hand (unless the abstract is separated from the paper, in which case "this" should still be used).

My reasoning for this is that the abstract is part of the paper (not in that the paper needs the abstract, but in that the abstract isn't meaningful without the paper).

Any other papers mentioned in the abstract would be mentioned using "that".