When citing from an inclusive range of two consecutive pages such as pages 25 and 26, one can write
I know this is a question of style, but I am having little luck with Google on this one. Is one much more common than the other? Is f only used with pages, or with lines of a poem and other references as well? Are there any rules which allow both to be used in different circumstances? Does CMoS have anything to say about this?
I am also aware of ff, but unlike f, there is no equivalent for “25ff” other than the strange-looking “25–” (no upper limit).
According to the MLA Style Manual✲ , 3d ed., 8.4, f./ff. after a page or line number means “and the following page(s) or line(s)”, but the abbreviation is “no longer recommended”; explicit page numbers are called for, e.g. 25-26. (Note that MLA now also deprecates use of p. and pp.)
Folio (abbreviated fol., but again, the abbreviation is “no longer recommended”) designates either a book published in the bifolium format (each full sheet of paper folded once to produce four pages) or a leaf of a manuscript or book.
MLA does not provide a citation format for unpaginated MSS or books; traditionally, this is done by folio number followed by r (for recto, the front or right-hand page of the leaf) or v (for verso, the back or left-hand page of the leaf), thus: 12v-13r.
EDIT, to ameliorate the provinicialism of the foregoing:
✲ MLA, the Modern Language Association, is the leading professional association of US scholars in critical and historical studies of modern languages, and its Style Manual is followed by most publishers in those fields.
As I understand it, "pp 25 f" was a manuscript abbreviation of "pages 25-26", and pronounced (if necessary) as "pages 25 and following". When "f" was simpler to write than "-26", the abbreviation was useful: in these keyboard days, it seems a little affected to me. There was also "page 25 sq (sqq in plural)", or sometimes et seq, but really those are of interest only to historians.
By the way, folio was something different. A folio was a way of measuring books without using page numbers, and there were various versions: for example, in old English law, it was 500 words or so (I don't remember the exact number, but it was chosen to be an hour's work for a copyist), and a case might be in Folio 27 of the All England Law Reports for 1867, which is on page 13 of the printed volume; abbreviated to All ER 1867 20F or (nowadays) All ER 1867 13.
Every journal style sheet I have seen recently discourages use of f and ff. In this day of computerized bibliographies, with much bibliographic information coming from central databases, I think page range formats are headed for standardization away from use of f. This is all distinct from p. and pp., which are prepended regardless of the number or contiguity of the cited pages.
At the risk of saying something foolish, I won't attempt to answer the question myself. I understand that all three synchronically more or less equivalent and substitutable, but it would be quite nice to know the traditional usage notes on the abbreviations.
As far as I know, pg. is not an acceptable form, at least in formal writing. The correct forms are p. for a single page, and pp. for a range.
In many cases, actually, you don't need any of them. Quite commonly you'll find references in the form volume:page(s), like 5:204 or 8:99–108 (or, for works of a single volume, something like Blah Blah Blah 108).
The APA style of referencing, which I have most frequently used, requires that p. is used for single page references or citations (Book Title, p. 13) while for multiple pages you must cite it as (pp. 35-40). So p stands for page, pp stands for pages. I have not encountered pg to be used, but I do use it in informal note taking.
Per Strunk and White's Elements of Style, p. is used to denote 1 page, pp. to denote a range of pages. This form of citation is used when you are using brief/in text citations. Otherwise, one would use the citation style for the type of formal paper that you are writing, for example, MLA would be "don't do it wrong" (Author's Last name 45) where the numbers indicate the page number where the quote is found, and the author's full name will be listed (along with other details about the source) in your works cited list.