apostrophes: Smith and Browns' or Smith's and Brown's?

[MamaChris]

I can write "Smith's paper X". But if it has two authors, does that become "Smith and Browns' paper X" or "Smith's and Brown's paper X" (or some other combination I can't think of)? I have never known how to do this correctly, and am now writing to someone I know is a grammar pedant and don't want to continue my usual cowardly practice of restructuring the sentence! Thanks

I think it's actually Smith and Brown's

Because, for the purposes of the paper, Smith and Brown are one entity, so the apostrophe comes after the latter's name. As they are one thing, the apostrophe comes before the S.

Good luck.

bumping this in case anyone else has any ideas - has puzzled me too!

Yeah Billy and Millie wrote the report -

It is Billy and Millie's report.

Not Billy's and Millie's report.

Methinks.

Thanks squonk and Legoleia, makes sense. Now I can write to this guy without fear of pedantry in response