Do you need hard copies? I've got PDF files for all of these.
Well the 172R and Diamond DA40 are available for free on their respective web sites.
I've got a scan of the 172N. If you want it, it's yours just PM me.
just to make things clear you are looking for an AFM or a copy of a POH to use as reference.
for the N model: http://www.redskyventures.org/doc/cessna-poh/Cessna_172_C172N-1978-POH-S1to7-scanned.pdf