rationalskepticism.org

romansh wrote:

Evolving wrote:

aban57 wrote:you don't say "Paul (and his wife) are going on holidays"

Yes I do.

aban57 wrote: but "is"

No I don't.

Aban57 is wrong when he says "says", but he could well be right when he writes.
http://www.thepunctuationguide.com/parentheses.html

Yep, that's where I found this rule, but I was at work and didn't want to spend too much time on the forum there. The link makes sense orally, but I couldn't find a single site speaking (writing) about a rule on this matter.