neart + ?

Ya know after neart, the noun changes form- neart airgid instead of airgead for example.

Obviously you're using the plural with neart, lots of books, etc. and some things don't have a plural as such, as in 'money' as above, so you're writing 'neart airgid' which is the genitive all the time, but what about neart dictionaries, books, signs, etc.- do you use the genitive plural if the noun has one? or do ya always stick to genitive singular?