I'm studying for PDD after 1st fail of PPD but will be back at it soon. Just found one of the primary PPD NCARB reference books I didn't own yet for free online if anyone needs it:
PDF download link:
https://ia800707.us.archive.org/25/item ... ctures.pdf
Main download page where I found it, if that link doesn't work:
https://archive.org/details/BuildingStructures/page/n17