A riddle for the weekend.
If p stands for one page, pp stand for a range of pages, which one should I use in a footnote with J. Jones, page 21 and other pages? I.e. do I write pp. 21 and further or p. 21 and further?
If you're going to use the initial page, and not specify the other pages, I'd use a single p; if you're going to specify all of the pages, I'd use the doubled pp. So, "p. 21 and following", but "pp. 21, 23-24, 27, 29."
I would discourage the use of "further" in a footnote in favor of "following", as "further" has a connotation of distance, while "following" has a connotation of sequence. But since it is fairly common to use the Latin terms ibid and op. cit. in footnotes, I prefer the Latin "et seq." in place of following. YMMV.
If you insist on being thus vague with a page reference, the usual abbreviation would be “pp. 21ff.” Per MLA Style Manual and Guide to Scholarly Publishing, 3rd ed., § 8.4, p. 273:
[f., ff.] — and the following page(s) or line(s) (avoided in favor of specific page or line numbers)
“et seq.” and “et seqq.” are likewise bracketed as “no longer recommended” in the same list.