Could you tell us the name of at least one, please?
Sure. I won't mention light-weight ESL textbooks, of course, but all the intermediate and advanced ones I've taught from give the proximity principle for concord with subjects introduced by correlative
either . . . or . . .
So far, in response to the OP's inquiry, I've only bothered to check three more serious sources, but I'd be happy to check more.
A Comprehensive Grammar of the English Language (1985, by Randolph Quirk and others) contains the following discussion:
"[4] Either your brakes or your eyesight (is / ?are) at fault.
[5] Either your eyesight or your brakes [are / ?is] at fault.
"A dilemma arises when one member is singular and the other plural (as in [4] and [5]). Notionally, or is disjunctive, so that each member is separately related to the verb rather than the two members being considered one unit, as when the coorinator is additive and. Since the dilemma is not clearly resolvable by the prinicples of grammatical concord or notional concord, recourse is generally had to the principle of proximity: whichever phrase comes last determines the number of the verb, as in [4] and [5]" (section 10.4 1, page 762).
Michael Swan, in the third edition of
Practical English Usage, states essentially the same principle in Section 532.2 (p. 525):
"When two subjects are joined by or the verb is usually singular if the second subject is singular, and plural if it is plural. Compare:
There's no room -- either two chairs or a table has got to be moved.
There's no room -- either a table or two chairs have got to be moved."
The book I have which not only gives the proximity principle but also mentions the preferability (or usualness) of using the plural NP before the verb in such cases was written by a nonnative speaker of English; however, he is an awesome grammarian, especially when it comes to the tenses and conditionals and copular sentences and clefts. He writes:
"When the subject consists of NPs conjoined with or, nor, either . . . or, neither . . . nor and not only . . . but also, the verb takes the number of the NP that is nearest to the verb (= proximity concord).
e.g. Either you or he is mistaken. [. . .]
Either John or I have to be there tomorrow. (*has)."
He gives the following footnote on the same page:
"When one NP is singualr and one is plural, the plural NP is normally placed second.
e.g. cp. ? Neither they nor Bertram wants to participate.
Neither Bertram nor they want to participate" (p. 238).
That's quoted from
A Comprehensive Descriptive Grammar of English, by Renaat Declerck (1991, Kaitakusha).
Lastly, I find the same principle in
Garner's Modern English Usage, by Bryan Garner (4th Edition, 2016, page 324):
"Nouns framed by either . . . or take a singular verb when the noun closest to the verb is singular, but a plural verb when that noun is plural -- e.g.:
- 'What hapens when grown children continue to pull on mom's apron strings or play on her 'mom guilt' for longer than either they or she needs?' Ruth Walsh, "Magazine's 'Mover and Shaper' to Speak," St. Petersburg Times, 5 Jan. 1994, at D2.
- 'He gives every sign of not stopping until either he or they are thoroughly defeated.' Marianne Means, 'Investigators Waiting in the Wings,' Rocky Mountain News (Denver), 3 Nov. 1996, at A81."
"But where the coordinates are of different number neither singular nor plural agreement feels right: whichever we choose, there will be conflict between the number of the verb and the number of one of the coordinates. Usage manuals generally invoke the principle of proximity, saying that the verb should agree with the nearest coordinate. This rule would select are in [ii] [Either the twins or Mary is sure to go] and is in [iii] [Either Mary or the twins are sure to go]. In practice, however, many speakers tend to feel uncomfortable with both forms and will tyically find ways of avoiding the conflict . . ." (p. 509).
I wonder if Huddleston and Pullum realize that their predecessors (Quirk et al.) have the proximity principle for either . . . or in their 1985 comprehensive grammar. Surely H&P don't mean to downgrade Quirk et al. to a mere "usage manual"! Incidentally, to be extra fair, I found another passage in support of Emsr2d2's perspective in an excellent traditional grammar book published in 1954 -- Understanding Grammar, by Paul Roberts:
"When one substantive is plural and the other singular, the verb theoretically agrees with the nearer substantive:
Either Mrs. Flick or her daughters have received the money.
Either the girls or their mother has received the money.
Actually, few self-respecting authors would write either sentence, for the decision is easily evaded: 'Either Mrs. Flick received the money or her daughters did'" (p. 278).
In conclusion, the point appears to be somewhat controversial.
